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New national strategies for hospital infection control : a critical evaluation 1992

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New National Strategies for Hospital Infection Control: A Critical Evaluation by David Wayne Birnbaum B.A., The University of California at Berkeley, 1966 M.P.H., The University of Minnesota, 1974 A THESIS SUBMITTED IN PARTIAL FULFILLMENT OF THE REQUIREMENTS FOR THE DEGREE OF DOCTOR OF PHILOSOPHY in THE FACULTY OF GRADUATE STUDIES INTERDISCIPLINARY STUDIES PROGRAMME EPIDEMIOLOGY, STATISTICS, MICROBIOLOGY and INFECTIOUS DISEASES] We accept this thesis as conforming to the required standard THE UNIVERSITY OF BRITISH COLUMBIA February 1992 Q David Wayne Birnbaum, 1992 Signature(s) removed to protect privacy In presenting this thesis in partial fulfilment of the requirements for an advanced degree at the University of British Columbia, I agree that the Library shall make it freely available for reference and study. I further agree that permission for extensive copying of this thesis for scholarly purposes may be granted by the head of my department or by his or her representatives. It is understood. that copying or publication of this thesis for financial gain shall not be allowed without my written permission. (Signature) .t/ c,F’4I’ •‘ 1hr,5; S ‘5’9 5rj /*V’e Department of pti#v1’ C’ 44’vf/1 7#2(r- The University of British Columbia Vancouver, Canada Date “9 49— DE-6 (2/88) Signature(s) removed to protect privacy PERMISSION TO USE COPYRIGHTED MATERIAL Permission is hereby granted to (Name of author of thesis) Dav:Ld. Wayne Birnbaum (Title of thesis) New National StrategiLes for Hospital Infection Control: A Critical Evaluation University of British Columbia (Degree) and to the National Library of Canada to reproduce (Figure/page numbers) text, & figures, pages 465—472 in (Title of article/book) Adoption of Guidelines for Universal Precau;tions and Body Substance Isolation in Canadian Aeute—Care Hospitals (Name, issue number, and year of journod) INFECT CONTROL HO:SP EPIDE1VITOL, 11(9), 1990 (Place, publisher and year of book) Return this form to: Library — Special Collections — Thesis Supervisor 1956 Main Mall University of British Columbia Vancouver, B.C. Canada V6T 1Z1 The National Library will lend or sell copies of the microfilm. All other publication rights are reserved. Ph.D. (Year) 1992 which will appear in this thesis. (Signatures) Address Signature(s) removed to protect privacy PERIs’IISSION TO USE COPYRIGHTED MATERIAL Permission is hereby granted to (Name of author of thesis) David Wayne B irnbauin (Title of thesis) Nw NatiniStrategies for Hospital Infection Control: A Critical Evaluation University of British Columbia (Degree) Fit. D. (Year) 1992 and to the National Library of Canada to reproduce (Figure/page numbers) text & figures, pages 319—326 in (Title of article/boolç) Epidemiologic Typing Systems for Coagulase—Negative Staphylococci (Name, issue number, and year of puma!) INFECT CONTROL 110SF EPIDEMIOL, 12(5), 1991 (Place, publisher and year of book) Library — Special Collections — Thesis Supervisor 1956 Main Mall University of British Columbia Vancouver, B.C. Canada V6T 1Z1 The National Library will lend or sell copies of the microfilm. All other publication rights are reserved. which will appear in this thesis. (Signatures) Address Return this form to: Signature(s) removed to protect privacy In presenting this thesis in partial fulfilment of the requirements for an advanced degree at the University of British Columbia, I agree that the Library shall make it freely available for reference and study. I further agree that permission for extensive copying of this thesis for scholarly purposes may be granted by the head of my department or by his or her representatives. It is understood that copying or publication of this thesis for financial gain shall not be allowed without my written permission. (Sigi I4-1 DepartmenU of 4I4( #Ap1g. The University of British Columbia Vancouver, Canada Date 72 DE-6 (2/88) Signature(s) removed to protect privacy Effectiveness of Infection Control Strategies Abstract: Isolation of those ill with contagious disease has been a fundamental infection control concept for hundreds of years. However, recent studies suggest that fewer than 50% of health—care workers comply with their hospital& isolation precaution policies and that efficacy of some of those policies is questionable. In response, two new systems, based upon fundamentally different goals, were promoted. The Centers for Disease Control, prompted by health—care worker& concerns about occupational risk of human immunodeficiency virus (HIV) from a growing number of patients with acquired immunodeficiency disease syndrome (AIDS), issued formal guidelines in 1987. This formed the basis for Universal Precautions (UP), a unifying strategy for precautions with all patients regardless of diagnosis intended to reduce risk to hospital staff members. Also in 1987, one hospital issued guidelines for Body Substance Isolation (BSI), hygienic precautions to be used with all patients based on recognition that colonized body substances are important reservoirs for cross—infection to both patients and staff members. These new strategies have been promoted widely, but there have been no formal assessments to reconcile controversies they raised nor to confirm their effectiveness. Further, necessary assessment tools have not been validated. This thesis provides new tools and new information to address three vital questions: Have hospitals adopted Universal Precautions or Body Substance Isolation? Do their staff members use the new system of precautions in daily practice? Has reliable use of a new system led to decreased risk of infection? A confidential mailed survey of all acute—care Canadian hospitals was conducted to measure rates of guideline receipt and adoption. It also obtained information on motivations for and perceived effectiveness of strategies adopted. Page ii Effectiveness of Infection Control Strategies A self—selected group of responding hospitals subsequently participated in standardized covert observation of their nurses infection control practices, then had the observed nurses complete a test examining their knowledge and beliefs. Employee health records were also examined to determine whether needlestick injury rates had changed since adoption of a new infection control strategy. Most Canadian hospitals adopted and modified new strategies based upon reasonable but unproven extensions of logic to protect health—care workers from HIV. 74% claimed UP (65%) or BSI (9%) but only 5% of 359 claiming UP and 0 of 50 claiming BSI adopted all policies expected. Many hospitals had not received key guideline publications. Guideline source, hospital size, and other variables were significantly associated with receipt. Nurses in 35 hospitals were observed to wear gloves during only z60% of procedures in which gloving was expected; rates varied widely among hospitals. Direct examination of sharps disposal containers confirmed compliance with a policy to not recap used needles (taken as recapping rate of 25%) in only 47% of 32 hospitals. Paired analysis of needlestick injury rates in 11 hospitals during comparable 90—day periods before versus after implementing UP/BSI showed no significant difference. 489 nurses completing a written test achieved their highest scores and least discordance among questions regarding procedural issues established long before UP/BSI, and lower scores or greater discordance on UP/BSJ concepts of philosophy, risk recognition and newer procedures. Positive correlation between knowledge and practice was not evident. UP and BSI now mean different things in different hospitals and have not been effective in harmonizing health—care workers’ infection control practices. Carefully standardized assessment methods are needed to guide their evolution to cost—effectiveness. Page iii Effectiveness of Infection Control Strategies Table of Contents: Abstract List of Tables Vi List of Figures viii Acknowledgements ix Preface X I. Introduction: Strategies for Hospital Infection Control Evolution of New Strategies for Infection Control Universal Precautions and Body Substance Isolation Current Knowledge of Hospital Infection Control Practices Scope and Limitations of Thesis Research II. Have Hospitals Accepted New Infection Control Strategies? 8 Receipt and Adoption of Guidelines by Canadian Hospitals Materials and Methods Results Response Rate in the Survey of Canadian Hospitals Receipt of Published Guidelines by Canadian Hospitals Adoption of Guidelines for UP and BSI Rationale for Adopting a New Strategy Other Perceptions — Disposal of Sharps Other Perceptions — Knowledge of Costs and Benefits Summary of Major Findings III. Have Hospital Staff Members Accepted the New Strategies? 27 Infection Control Practices of Critical Care Nurses Materials and Methods Results Response Rate Use of Gloves Handling of Used Disposable Needles Summary of Major Findings Knowledge and Beliefs of Critical Care Nurses Materials and Methods Results Response Rates Nurses Knowledge and Belief Scores Relationship Between Knowledge and Practice Summary of Major Findings Page iv Effectiveness of Infection Control Strategies Table of Contents (cont.): IV. Have New Infection Control Strategies Reduced Infection Risks? 49 Epidemiologic Assessment of Risk to Hospital Staff— Needlestick Injuries Materials and Methods Results Summary of Major Findings Epidemiologic Assessment of Risk to Hospital Patients Tracing the Sources of Infection by Microbiologic Methods V. Discussion 55 Validity, Reliability, Power and Generalization of This Research Have Universal Precautions or Body Substance Isolation Been Effective as Harmonizing Strategies for Hospital Infection Control? Recommendations for Improving the Research Tools VI. Conclusions and Recommendations 80 Recommendations for Improving New Infection Control Strategies VII. Bibliography 85 VIII. Appendices Appendix 1: Conceptual Models 93 Comparison of Isolation Strategies Infection Control Goals, Objectives and Assumptions Appendix 2: Hospital Survey Questionnaire Forms 96 Appendix 3: Nurse& Knowledge and Belief Test Forms 103 Appendix 4: Efficacy of MIDI for Epidemiologic Typing of Staphylococcus epidermidis 113 Page v Effectiveness of Infection Control Strategies List of Tables: Table 1: Evaluation Criteria 4 Table 2: Policy Recommendation versus Infection Control Strategy 10 Table 3: Survey Response Frequency and Rate by Bed Size Group and Province for Non—Specialty Acute—Care Canadian Hospitals 16 Table 4: Receipt of Guidelines by Source and Hospital Size 17 Table 5: Hospital Size vs ICP Staffing (in FTE) 19 Table 6: Percent of Hospitals Claiming Adoption of New Strategies 19 Table 7: Adoption of Guidelines by Hospital Size 21 Table 8: Percent (Number) of Hospitals Adopting Policies Expected under UP, BSI and Traditional Strategies 22 Table 9: Infection Control Strategy Claimed versus Practiced 22 Table 10: Predominant Method for Transporting Used Needles from the Point of Use to the Point of Disposal, by Hospital Size According to Number of Beds 25 Table 11: Perceived Effectiveness of Strategies To Avoid Recapping of Used Needles 25 Table 12: Nursing Care Procedures Observed 30 Table 13: Frequency of Recapped Needles in Disposal Containers 33 Table 14: Characteristics of Participating Hospitals 37 Table 15: Relative Ranking of Knowledge Test Section Scores 38 Table 16: Spearman Correlation Coefficients Between Test and Practice Scores 47 Table 17: Canonical Variate Coefficients and Correlations 48 Table 18: Typing Methods for Coagulase—Negative Staphylococci 54 Table 19: Magnitude of a— and 13—error for Hypothesis #3 59 Table 20: Status of UP/BSI in Canadian Acute—Care Hospitals, 1990 76 Page vi Effectiveness of Infection Control Strategies List of Tables: (cont.) Table 21: Comparison of Isolation Strategies 94 Table 22: Infection Control Program Objectives and Assumptions 95 Table 23: Characterization of Epidemiologically—Related Isolates by Lab of Origin 125 Table 24: Summary of MIDIs Typing Performance 126 Page vii Effectiveness of Infection Control Strategies List of Figures: Figure 1: Hospitals Motivations for Adopting UP or BSI 23 Figure 2: Frequency of Observed Glove Use During Types of Nursing Care 32 Figure 3: Effectiveness of Hospitals’ In—Service Program 39 Figure 4: Tukey Sum—Difference Graph of Correct Response Frequencies 40 Figure 5: Nurses’ Overall Test Score, by Site (Ordered by Region and Size) 42 Figure 6: Nurses’ Overall Test Score, by Personal History Claims 45 Figure 7: Spearmans Correlation Coefficient (of Knowledge and Practice Scores) vs Minumum Number of Practice Observations Required for Inclusion in Analysis 48 Figure 8: Needlestick Injury Rates in 11 Hospitals Providing Paired Data 52 Figure 9: Magnitude of Confounding in Nurses’ Test Scores 61 Figure 10: Normal Probability Plot— Distribution Rejected by the Kolmogorov—Smirnov Test 62 Figure 11: Distribution of Phi Coefficients for 11 Paired Responses, by Site, in 22 Sites Returning 10 Tests 64 Figure 12: Section of MIDI Dendrogram Containing Group 5 Isolates 127 Figure 13: Joining Distance of Repeated Assays 128 Page viii Effectiveness of infection Control Strategies Acknowledgement: Tasks of this magnitude cannot be completed without considerable encouragement and support. First and foremost, my family has been a partner in the endeavor: I would not have started nor lasted without you Connie, Dad, Jeremy and Jenny. Nor would I have reached this far without being stimulated and challenged by an exceptional group of teachers and colleagues. Dr. Chow, Dr. Kelly, Dr. Noble, Dr. Mathias, Dr. Schechter and Dr. Schulzer, I am in your debt. This work could not have been completed without the diligent support of infection control practitioners in participating hospitals throughout Canada, and was greatly facilitated by endorsement from the Canadian Hospital Association as well as the assistance of friends and colleagues in preparing and translating forms. Last but not least, I thank the Government of Canada for funding. This research was supported in part by the National Health Research and Development Program through a National Health Fellowship. Page ix Effectiveness of Infection Control Strstegies Preface: Parts of this work have been published as: Birnbaum DW, Schuizer M, Mathias RG, Kelly M, Chow AW. Receipt and Adoption of Universal Precautions and Body Substance Isolation Guidelines in Canadian Hospitals. Abstract #L22. 90th Annual Meeting, American Society for Microbiology, May 1990. Blrnbaum DW, Schuizer M, Mathias RG, Kelly M, Chow AW. Receipt and Adoption of Universal Precautions and Body Substance Isolation Guidelines in Canadian Hospitals. Abstract #C6, 3’rd Decennial International Conference on Nosocomial Infections, Atlanta, Georgia, July 1990 Birnbaum D, Schulzer M, Mathias RG, Kelly M, Chow AW. Adoption of Guidelines for Universal Precautions and Body Substance Isolation in Canadian Acute—Care Hospitals. INFECTION CONTROL AND HOSPITAL EPIDEMIOLOGY 1990;11(9):465—472 Birnbaum D, Schuizer M, Mathias RG, Kelly M, Chow AW. New infection control strategies in acute care. DIMENSIONS IN HEALTH SERVICE 1 990;May:26—29 Birnbaum D, Schuizer M, Mathias RG, Kelly M, Chow AW. Needlestick injury: do preventive measures work? DIMENSIONS IN HEALTH SERVICE 1990;Nov.:29—32 Birnbaum D, Kelly M, Chow AW. Epidemiologic Typing Systems for Coagulase— Negative Staphylococci. INFECTION CONTROL AND HOSPITAL EPIDEMIOLOGY 1991; 12(5):3 19—326 The research concepts, designs and execution were the original work of David Birnbaum; co—authors provided valuable constructive criticism, supervision of directed readings and logistical support. Page x Effectiveness of Infection Control Strategies I. Introduction: Evolution of New Strategies for Infection Control Universal Precautions and Body Substance Isolation Segregation and isolation of those ill with contagious diseases has been a fundamental part of infection control for hundreds of years.1 Over the last thirty years. a number of monographs and books from the American Public Health Association, American Hospital Association, the Centers for Disease Control (CDC) in Atlanta, and the Laboratory Centre for Disease Control (LCDC) in Ottawa codified specific isolation techniques for use in hospitals based upon this heritage and various extensions of logic. However, relatively few of today’s hospital—acquired (nosocomial) infections are contagious or even communicable; most, in fact, are latrogenic or endogenous (originating from treatments or a patients own flora). Nevertheless, isolation of patients diagnosed or presumed as infectious rapidly became a mainstay of hospital infection control efforts in spite of an absence of proof that isolation per se reduces the risk of nosocomial infection.2 However, in light of persistent absence of proven effectiveness for various infection control measures, some experts began to question their continued use.3 In response, the CDC initiated a project to review and revise infection control guidelines on the basis of expert consensus on interpretation of clinical or research studies. Notably, the revised CDC Guideline for Isolation Precautions in Hospitals “did not rank the recommendations by the degree to which they have been substantiated by scientific data or the strength of the working group’s opinion on their effectiveness or practical value.”4 There were simply too few studies testing the efficacy or effectiveness of recommended measures. These revised guidelines offered hospitals a choice between the traditional Page 1 Effectiveness of Infection Control Strategies category—specific system and a potentially more user—flexible disease—specific system, and eliminated the traditional Protective Isolation category based upon proof that this time—honored isolation category was ineffective.8 In addition to an absence of studies demonstrating efficacy, a growing number of anecdotal reports and formal studies confirmed that compliance by health—care workers with their hospital’s policies for isolation precautions frequently was poor.6 Studies spanning the last ten years all suggest that fewer than 50% of staff complied with their hospitals’ isolation precaution policies.6 Over the last five years, two new systems were proposed based upon fundamentally different goals. In 1987. CDC consolidated its 1982—1986 recommendations in response to health—care workers’ concerns about acquiring human immunodeficiency virus (WV) infection from patients with acquired immunodeficiency disease syndrome (AIDS).7 This formed the basis of Universal Precautions (UP) for blood and body—fluids, a unifying strategy for precautions with all patients, regardless of diagnosis, intended to reduce risk to hospital staff members. It deals with blood—borne pathogens only, and is intended as a supplement to the CDC category— or disease—specific isolation system. Also in 1987, one hospital published its own recommendations for hygienic precautions to be used with all patients based on recognition that colonized body substances were important reservoirs for cross—infection to both other patients and staff members.8 Body Substance Isolation (BSO, developed In response to bacterial cross—infection problems in critical care units, is intended to reduce cross—infection risk with all pathogens, not just blood—borne agents, for all patients and health—care workers. BSI replaces the CDC category— or disease—specific systems. UP has been promoted widely by the CDC, LCDC, the Association of State Page 2 Effectiveness of Infection Control 5trate7ies and Territorial Public Health Laboratory Directors and others. BSI was promoted in a videotape distributed to hospital administrators by the American Hospital Association. Endorsements by such influential agencies have not considered these new systems to be equivalent.9 10 Subsequent UP guideline revisions’1 have neither reduced this controversy nor received universal acceptance.’2 Current Knowledge of Hospital Infection Control Practices Although numerous guidelines have been published, only one descriptive study reports the extent of their receipt and adoption among hospitals in the United States.’3 Patterns of receipt among Canadian hospitals are unknown. Even though at least 80% of all US hospitals had received and adopted CDC guidelines, compliance rates by their staff members with these measures, as noted above, tended to be under 50%. Increasing concerns about the safety of treating AIDS patients in hospital, and increasing doubts about effectiveness of current isolation precautions have brought North American hospitals to a new crossroad.’4 UP and BSI present new options and new controversies. The extent to which guidelines for these new systems have been reviewed by individual North American hospitals is unknown. Many infection control practitioners (ICP) believe that widespread variations In definitions and practices exist between hospitals, but the uniformity or quality of UP or BSI practice is also undocumented. Anecdotal reports suggest that UP and BSI have not succeeded as unifying strategies to improve compliance, but there have been no formal, multicenter studies. Standardized tools to survey these issues have not been validated. Therefore, expensive new strategies have been promoted widely for nearly five years in the absence of adequate tools or studies to document their implied effectiveness. Anecdotal reports, editorials and letters to editors reveal Pege 3 Effectiveness of Infection Control Strateg2es controversy, confusion and need for formal evaluation. Further, unproven guidelines may be mandated in accreditation requirements and legislative regulations.’5 This presents an urgent need for applied research in hospital epidemiology to guide administrative and infection control decisions. Scope and Limitations of Thesis Research This thesis investigates the effectiveness of UP and BSI as currently adopted in acute—care Canadian hospitals. It validates new survey tools and applies survey sampling and multivariate statistical methods in multi—center research. The approach involves examination of three basic criteria in operational aspects of structure, process, output and outcome (Table 1). Table 1: EVALUATION CRITERIA CRITERION STRUCTURE PROCESS OUTPUT OUTCOME 1. Hospitals have All have All have All know UP costs and received adequate received reviewed how UP benefits are information to CDC/LCDC CDC/LCDC and BSI identified in make informed guideline guideline differ each hospital decisions; for UP for UP Hospitals adopted Coherent appropriate policies policy—set consistent with the in place system adopted. 2. Hospital staff Hospitals Education High staff Staff accept understand and mandate provided scores on new system accept UP or BSI education to staff a test 3. Staff adhere to Hospitals Hospitals Gloves worn recommended UP or provide monitor for risk BSI guidelines in gloves, compliance procedures their daily work gowns, eye and provide practices; protection performance Used needles and devices feed—back not recapped Use of UP or BSI to discourage practices leads to needle recapping Fewer reduced infection needlestick risk, injuries after UP or BSI adopted Page 4 Effectiveness of Infection Control Strategies A number of important difficulties and limitations in this work must be noted. First, as implied earlier, UP and BSI are specific systems according to their respective published documentation, but are likely to mean different things as implemented in different hospitals. This research studies the effectiveness of UP and BSI as unifying strategies among all acute—care Canadian hospitals; it does not address efficacy nor superiority in reducing infection rates by some hospitals as opposed to others. Effectiveness is defined in terms of compliance, not reduction in nosocomial infection rates, for several reasons: a) Given logistic restraints and the number of confounding variables associated with nosocomial infection risk, it was not feasible to study before—and—after rate differences. Further, it would not have been possible to randomize assignment of infection control systems to perform a true experiment. b) Adequate microbiologic methods for tracking certain nosocomial pathogens are not available to support such epidemiologic investigation.lb Part of this thesis research investigates the potential of a novel microbiologic method that may provide such support in the future. c) As will be discussed later, the driving force motivating adoption of new systems has been a perceived occupational risk of HIV infection, not a desire to reduce risk of nosocomial infection in general. d) Finally, since it is not yet documented whether UP or BST have been adopted effectively, it is premature to focus evaluation on a long—term outcome (infection risk reduction) as opposed to short— term measures (improved compliance with reasonable policies). Page 5 Effectiveness of Infection Control Strategies Second, the representative nature of hospitals included in the study must be viewed with caution. UP or BSI were promoted widely before this research began. Individual hospitalst implementation costs and constraints, perceived needs and potential benefits are likely to vary widely as a function of hospital size and location. Infection control systems cannot be assigned in a randomized or blinded manner, and hospitals cannot be forced to participate. Likelihood, direction and extent of self—selection bias must be considered carefully. The study design must also achieve a balance between sample sizes large enough to generate convincing statistical power yet small enough to be practical. Third, target events must be selected with regard to reliability of detection and clear importance in testing relevant hypotheses. Since validated survey tools pertinent to this research were not available, an important part of the work involved development and validation of standardized questionnaires and sampling plans. Further, since there is no criterion ‘goldt’ standard against which to validate these tools, methods to achieve face, consensual and content validity are emphasized.17 Since opportunities to obtain repeated measurements in participating hospitals were very limited, other approaches to ensuring reliability are used.18 19 Finally, this work cannot provide a definitive answer as to whether UP or BSI can succeed. Ideally, infection control guidelines evolve as a function of experience and evaluation. The nature of patients, pathogens and procedures in hospitals is dynamic; precautions that have been in force may fall from grace as new information and situations add to our knowledge. Inadequacies of traditional isolation systems became well—recognized. This led to a natural experiment: New isolation systems were promulgated. My work provides new tools and new information to indicate what the new systems have achieved. Page 6 Effectiveness of Infection Control Strategies The underlying null hypothesis being tested is that UP and BSI have not achieved a uniform standard of effective infection control practice among acute— care hospitals in order to protect health—care workers or their patients. This is examined in several ways through survey of administrative practices, covert observation of workers practices, formal testing of workers’ knowledge and beliefs, self—reported disease—exposure histories and review of employee health incident reports. These data are used to test a number of subordinate hypotheses relating to the elements listed in Table 1. Appendix 1 provides conceptual models for hospital infection control strategies. The following chapters discuss hypotheses, methods and results as well as provide descriptive information about participating hospitals, their policies and their staff. Page 7 Effectiveness of Infection Control Strategies II. Have Hospitals Accepted New Infection Control Strategies? Receipt and Adoption of Guidelines by Canadian Hospitals UP and BSI involve radical departure from long—standing reliance upon isolation precautions, and they imply potentially large cost increases, so it is important that hospital administrators understand their ramifications. UP and BSI both stipulate that all patients are to be treated alike, thus eliminating a need for traditional “biohazard’ warning labels to prompt special isolation precautions, but they differ from each other in several important aspects. UP focuses on minimizing risk from blood—borne infections, primarily hepatitis B and liv, while BSI focuses on minimizing cross—infection risk with all pathogens for both patients and staff. UP applies only to those body fluids associated with hepatitis B or HIV transmission while retaining traditional isolation categories to protect against transmission of other diagnosed or suspected infections. It is, in fact, universal application of the traditional CDC category “Blood/Body Fluid Precautions’. BSI applies to all body substances and eliminates all other traditional isolation categories except that for infections spread by an airborne route. It promotes use of protective measures against risks identified on a procedure—specific rather than diagnosis—specific basis. BSI provides a detailed guide to patient placement based on evaluation of hygiene, cooperation, and disease susceptibility of patients and staff. BSI also originally emphasized gloving as an alternative rather than a supplement to handwashing, a view subsequently challenged20 21 Rates of receipt and adoption for infection control guidelines by Canadian hospitals had not been reported previously. Therefore, a first step in examining the effectiveness of UP and BSI as unifying strategies was to determine whether Canadian hospitals received and reviewed appropriate publications that define Page 8 Effectiveness of Infection Control Strategies these new strategies. Next, beyond simply estimating the proportion of hospitals claiming adoption of UP or BSI. the specific published guideline statements adopted by’ each hospital were compared with their claimed adoption of UP or BSI to provide a measure of how well these new unifying strategies have harmonized hospital infection control policies. Specific objectives of this administrative survey were to determine, by size groups, hospitals’ infection control information resources, current extent of adoption and evaluation of UP or BSI, motivation(s) for adopting a new strategy and knowledge of its cost implications. Materials and Methods: Sampling Frame and Questionnaire Mailing addresses for all Canadian hospitals and size distribution for non— teaching non—specialty hospitals were obtained from the 1988 Canadian Hospital Association (CHA) Directory. Size distributions for teaching and for pediatric hospitals were obtained from the Association of Canadian Teaching Hospitals and the Canadian Association of Paediatric Hospitals membership lists respectively. No data were available regarding the size distribution of 153 specialty hospitals. In March 1989, advance notice letters explaining the study’s purpose and assurance of confidentiality were mailed to the administrator of each acute—care hospital listed in the 1988 CHA membership directory. Questionnaires with cover letter and prepaid return envelope were sent two weeks later. Instructions requested that administrators forward the questionnaire to their infection control program director. A prompt for reply was published in Canada Diseases Weekly Report (CDWR) (April 15, 1989). A second prompt, using identical forms, was mailed to non—responders in July, 1989. The questionnaire, a 3—page self—report form, examines consideration and adoption of specific, major, referenced infection control guidelines and Page 9 Effectiveness of Infection Control Strategies recommendations. It had been pretested and modified for clarity before use, and was provided in English and French versions (see Appendix 2). A combination of open—text short responses and closed—response check—off’ boxes was used. Specific terms (i.e.: Universal Precautions, Body Substance Isolation) were purposely left undefined to test respondents’ knowledge. Questions used to distinguish between UP, BSI and Traditional strategy related to types of body fluids perceived as potentially hazardous; to discontinuation of special “isolation’ warning labels for soiled linen, specimens and waste; and to routine glove use and handwashing. The strategy claimed in open—text responses was compared with objective assignment to the UP, BSI or Traditional strategy, based upon the specific combinations of fundamental policy adoptions recorded in response to closed—response questions (Table 2). TABLE 2: Policy Recommendation Versus Infection Control Strategy INFECTION CONTROL STRATEGY: POLICY RECOMMENDATION: UP BSI TRADITIONAL 1. No special warning labels on laboratory specimens, waste or soiled—linen bags + + — 2. Gloves as alternative to handwashing — + — 3. Private Room for staphylococcal pneumonia ± — ± 4. Precautions limited to specific body fluids + — — The effect of not adopting a policy to train all staff was also examined. Responding and nonresponding hospitals were compared on the basis of size, location (province, setting), and accreditation status to assess the impact of self—selection bias. Coding of Responses Completed questionnaires were marked with unique sequential numbers upon receipt, and these data were stored on computer. Databases were maintained Page 10 Effectiveness of Infection Control Strategies with an interactive program written in FoxBASE+ (version 2.00, Fox Software, Perrysburg, Ohio); FoxDOC (Fox Software, Perrysburg, Ohio) was used in documenting and debugging the code. Replies with any one of the three pages left blank were not used. Missing responses were coded differently from negative responses to questions concerning guideline receipt and review; policy adoption was coded only if an explicit “yes” was indicated (“no’ or non—response to the single items, or any indication that adoption was planned for a future date rather than actually achieved by the survey date were coded as not having adopted a guideline). Grouping by number of beds was assigned using the same ranges as CHA and Statistics Canada: 1—24, 25—49, 50—99, 100—199, 200—299, 300+; and the latter further divided into 300—499 vs 500+ to facilitate comparison with a survey of US hospitals by Celentano and colleagues.13 Total bed number may include long—term as well as acute beds; to be included in the sample, an institution must provide acute care service(s). Coding of claimed infection control strategy (UP, BSI, “Traditional”) and rationale for that choice was based upon responses to open—text questions. If no indication was given of adopting one of the newer strategies, the response was coded as “Traditional”. An indication of formal or informal use of UP or BSI was coded as adoption; indication of consideration rather than use per se was coded as “Traditional”. Several Ontario hospitals indicated using “Body Substance Precautions” rather than “Body Substance Isolation”; if their response mentioned retaining category— specific isolation, then they were coded as UP, otherwise as BSI. Some hospitals indicated using both UP and BSI, which is self—contradictory; they appear to be using UP without accepting limitations upon which body fluids are considered “infectious” and were therefore coded as UP. Reasons given by each site for Page 11 Effectiveness of Infection Control Strategies adopting UP or BSI were coded under one or more of the following motives: 1) Staff Protection, 2) Patient Protection , 3) Compliance with a standard of practice expressed in expert guidelines, and 4) Miscellaneous. Two survey questions were asked in relation to discouraging a contra— indicated practice of recapping of used needles. One asked whether the respondent felt that at least half of ward staffs still recap used needles regardless of policy. A second asked what type of disposal containers were provided and how needles were transported from the point of use. The extent to which Canadian hospitals have adopted practices and protective equipment that may be effective in reducing needlestick injury risk had not been reported previously. Responses to the second question were coded as either: a) Bedside containers — Point of Use” disposal, in container either mounted in each patient room or small special units hand—carried to each patient; b) Carry unsheathed — used needles to be carried unsheathed by hand or on standard trays (e.g.: K—basin) to disposal containers located in utility areas and/or on medication carts; c) Recap and carry — used needles recapped, emphasizing no particular technique, and carried by hand or tray to central disposal containers; d) Safe Recapping — “Thimble Technique” or other one—handed method or provision of special recapping devices for recapping prior to transport; e) Foam Stabbing Block — Used needle stabbed into small containers of rigid foam for transport (unsheathed) to central disposal containers; f) Special Trays — Specially designed tray to support used needles safely during transport to central disposal containers; g) Not Specified — Predominant system not evident from description provided. If two systems were described in a given hospital, the system most immediate to Page 12 Effectiveness of Infection Control Strategies the point of use was coded (e.g.; safe recapping and carry unsheathed in K— basins would be coded as safe recapping; foam block and bedside (wall—mounted) containers coded as foam block; etc.). Statistical Analysis Point estimates and 95% confidence intervals for guideline receipt rates in the sample received were calculated using poststratification and normal approximation to the binomial distribution. Poststratification is a survey sampling technique that adjusts for the effect of applying stratification in the analysis rather than in the sampling step.22 Stratification refers to division into subdomains (strata), in this case into hospital size groups by number of beds. The finite population correction factor was applied to variance calculations. Conservative correction for non—response was also applied to confidence intervals by assuming that all nonresponders had received guidelines.22 This represents an extreme case correction. Approximated confidence intervals were also confirmed by exact probabilities computed with P— EXACT software (Kern International) using the hypergeometric distribution with both the classic and Miettinen’s mid—p algorithm.23 Unlike the classic algorithm, the mid—p algorithm adds only half of the probability associated with an observed distribution to the probabilities associated with all more extreme distributions. Data extraction and simple descriptive statistics were executed with R&R Relational Report Writer (version 3)(Concentric Data Systems Inc., Westborough Massachusetts). Cross—tabulations of responses were analyzed by log—linear analysis, a multivariate technique that models the expected cell values in a multidimensional contingency table from information regarding a number of categorical variables and their interactions. Log—linear models were fitted and Page 13 Effectiveness of Infection Control Strategies evaluated by chi—square tests using SAS (version 6.03)(SAS Institute, Cary, North Carolina). SYSTAT (version 4.1) (Systat. Inc., Evanston, Illinois) was also used for table analysis with chi—square goodness of fit tests and for Spearman’s correlation coefficients between guideline receipt or adoption rates and size. BMDP (BMDP Statistical Software, Los Angeles, California) was used for step—wise logistic regression in order to examine size as an interval as well as a categorical variable and to support inclusion of other variables as predictors of guideline receipt. Hypotheses Tested Null hypothesis #1: Canadian hospitals show no significant differences in rates for receipt of published guidelines defining UP and BSI in association with hospital size or location. The alternative hypotheses is that receipt rates differ by hospital size and/or location. A related objective was to measure Canadian hospitals’ receipt rates for recent CDC or LCDC guidelines in comparison to American hospitals’ receipt rates for previous CDC guidelines in order to determine whether all hospitals receive this fundamentally important information. Null hypothesis #2: Canadian hospitals show no preference among infection control strategies (Traditional, UP or BSI). The alternative hypothesis is that a majority have adopted either a Traditional system or one of the new systems. A related objective was to compare each hospital’s claim of system used against specific policies they adopted in order to determine whether hospitals implemented their infection control strategy coherently and completely. Results Response Rate in the Survey of Canadian Hospitals A set of mailing labels for all Canadian hospitals was obtained from CHA. The population sampled consisted of 943 acute—care hospitals after 61 labels Page 14 Effectiveness of Infection Control Strategies were discarded for specialty hospitals listed as providing long—term care only or for duplicate addresses (i.e.: parent corporation as well as sites operated by the corporation). 454 responses were received after the first mailing (48% response rate), and another 125 from a second mailing for a total of 579 (61%). Among the 579, 10 indicated provision of long—term care only and these were excluded. Of the remaining 569 responses from acute—care hospitals, one site was not yet in operation and another 12 were excluded as insufficient completion of the forms. These exclusions occurred in the three least bed—size groups. Table 3 summarizes the hospital sampling frame and distribution of responses by hospital size and province. The size distribution of responders approximates that of all Canadian hospitals. The composition expected versus received for the 1—49, 50—99, 100—199, 200—299, and 300 bed groups were 43% vs. 33%, 18% vs. 19%, 14% vs. 16%, 8% vs. 9% and 16% vs. 23% respectively. Mean response rate for urban centers was z80%, with 94% of the largest hospitals responding and lower response rates from smaller and rural hospitals. Receipt of Published Guidelines by Canadian Hospitals Correlations between rate of receipt for published guidelines and both the hospital size and type of publication are evident in Table 4. Receipt rates increased as a function of hospital size, but different publications’ receipt rates were not equal. Federal publications were received more commonly than topical review or medical journals. Two federal publications, CDWR and Morbidity and Mortality Weekly Report (MMWR), are key sources of information that provide primary documentation for UP protocols and timely updates of CDC or LCDC recommendations. Their receipt was dependent on hospital size (p<0.001, chi—square test). Log—linear analysis was used to examine the relation between receipt of CDWR or MMWR and hospital Page 15 Effectiveness of Infection Control Strategies Table 3: Survey Response Frequency and Rate by Bed Size Group and Province for Non—Specialty Acute—Care Canadian Bospitals* BED BRITISB BEN NEVPOUNDLAND/ NOVA NNT/ PRINCE EDNARD ALL SIZE ALBERTA COLUMBIA MANITOBA BRUNSN1CK LABRADOR SCOTIA YUKON ONTARIO ISLAND QUEBEC SASKATCEENAN PROVINCES GROUP (118) (93) (77) (32) (35) (45) (7) (189) (7) (121) (132) (856) + 1— 49 27 22 23 4 5 5 3 25 1 4 37 168 42% 60% 40% 33% 25% 31% 50% 69% 33% 29% 35% 46% 50—9921 9 5 7 4 7 2 28 0 3 8 101 63% 56% 71% 78% 80% 64% 100% 65% 0% 18% 79% 65% 100—199 12 13 5 2 2 13 0 23 1 10 6 88 100% 100% 81% 50% 56% 100% + 67% 100% 33% 100% 75% 200—299 2 10 3 4 1 2 0 17 0 9 1 49 83% 93% 100% 100% 56% 56% + 71% 43% 28% 69% 300+ 10 14 5 4 4 1 0 47 1 32 7 129 100% 85% 91% 100% 100% 40% + 91% 100% 84% 100% 94% ALL 72 68 41 21 16 28 5 140 3 58 59 535 GROUPS 61% 73% 53% 66% 46% 62% 71% 74% 43% 48% 45% 63% NOTE: * Table excludes 10 responses fran chronic care sites, 1 from a site under construction, 12 incomplete responses fran acute—care sites, and 21 responses from specialty hospitals. + Total number of non—specialty hospitals listed for each province is shoin in parentheses. Row totals include 24 responses fran unknown provincial location. + Indicates no hospitals in category. Page 16 Effectiveness of infection Control Strategies TABLE 4: Receipt of Guidelines by Source and Hospital Size BEDSIZE GROUP: POLICY AREA AND SOURCE <25 25—49 50—99 100—199 200—299 300—499 500+ Number of facilities: 80 103 105 89 50 79 50 ISOLATION ROOM REQUIREMENTS 25 40 50 61 36 62 45 CDC ISOLATION GUIDELINE 31% 39% 48% 69% 72% 78% 90% ISOLATION ROOM REQUIREMENTS 23 46 65 58 36 53 47 LCDC ISOLATION GUIDELINE 29% 45% 62% 65% 72% 67% 94% HAZARDOUS BODY FLUIDS LISTED 9 44 49 64 39 75 48 HNWR 1988;37:377 11% 43% 47% 72% 78% 95% 96% WARNING LABELS - LABORATORY 25 48 69 69 43 73 48 CDWR 1987;13S3 31% 47% 66% 78% 86% 92% 96% WARNING LABELS- HOUSEKEEPING 14 23 41 47 33 51 37 ASEPSIS 1986;8:2 18% 22% 39% 53% 66% 65% 74% GLOVING VERSUS HANDWASHING 7 17 14 26 17 43 37 ANN INTERN NED 1987;107:243 9% 17% 13% 29% 34% 54% 74% STAFF EDUCATION 17 36 35 41 28 51 42 N ENGL J NED 1986;315:1562 21% 35% 33% 46% 56% 65% 84% CDC or LCDC GUIDELINE Rec’d 43% 56% 75% 82% 90% 87% 98% Reviewed if Received 76% 84% 86% 92% 89% 96% 96% CDWR or HNWR Received 34% 62% 76% 85% 90% 97% 98% Reviewed if Received 89% 89% 88% 96% 96% 96% 96% Page 17 Effectiveness of Infection Control Strategies characteristics in addition to number of beds. Regional location and rural versus urban setting were not significant factors (p>O.50), but presence of an infection control practitioner (ICP) was associated with guideline receipt (p<0.000l). The vast majority of Canadian ICPs receiving a guideline reported reviewing it. Backward step—wise multiple logistic regression was used to examine hospital size as an interval variable and to include more variables than could be accommodated in a log—linear model. Default probability limits to remove or enter terms were used (0.15 and 0.10 respectively). Regression models started with receipt of CDWR or MMWR as the dependent variable and size, presence of an ICP, presence of intern or resident teaching programs, provision of risk services (e.g.: dialysis, sexually—transmitted disease clinic, etc.) and interactions as independent variables. In decreasing order of significance, terms retained in all final models were size, presence of an ICP and presence of medical teaching programs. Provision of risk services was dropped as not significant in all models, and interaction terms dropped in all but two (ICPsize was retained when size was expressed as the logarithm of the group median; ICPsize and teachingsize were retained when size was expressed as an arbitrary 7—level categorical variable in an asymptotic but not in maximum likelihood regression). One—third of hospitals under 200 beds had received neither MMWR nor CDWR (mean receipt rate 63%, 95% confidence interval with finite population correction 61% to 65%, and with very conservative correction for nonresponse 61% to 81%). An exact upper limit was within 1 percentage point of the approximation. In addition to this low receipt rate, these smaller hospitals were also the least likely to have their own full—time ICPs (Table 5). Page 18 Effectiveness of Infection Control Strategies Table 5: Hospital Size vs ICP Staffing (as Full Time Equivalents) Number of Infection Control Practitioners: Number of Beds <25 25— 49 50— 99 100—199 200—299 300—499 500+ All Sizes Adoption of Guidelines for UP or BSI The proportion of hospitals claiming adoption of UP or BSI rose progressively by size group (Table 6, p<0.001, chi—square test). Overall, 359 0.0 <1.0 1.0 1.5 2.0 2.5 3.0 3.5 4.0 65.0% 31.3% 3.8% 32.0 58.3 9.7 28.6 62.9 8.6 13.5 64.0 21.4 1.1 2.0 50.0 44.0 4.0 — — — — 1.3 26.6 58.2 6.3 6.3 — — 1.3 — 2.0 6.0 36.0 10.0 26.0 2.0 14.0 2.0 2.0 23.4 46.2 22.8 2.3 3.2 0.2 1.3 0.4 0.2 Hospitals Claiming Adoption of New Strategies STRATEGY CLAIMED: UP BSI Traditional TABLE 6: Percent Of NUMBER OF BEDS <25 25— 49 50— 99 100—199 200—299 300—499 500+ TOTAL: 43.6% 1.3% 55.1% 62.1 6.8 31.1 76.9 3.9 18.3 69.7 11.2 19.1 69.4 10.2 20.4 64.1 15.4 20.5 61.2 22.5 16.3 64.4 9.1 26.4 Page 19 Effectiveness of Infection Control Strategies (64.4%) claimed UP and 50 (9.1%) BSI, ranging from 44.9% claiming UP or BSI in the <25—bed group to 83.7% in the 500—bed group. Unlike receipt of guideline publications, a positive, correlation between hospital size and affirmative response was not evident for adoption of individual policy guidelines (Table 7). Fundamental policy differences between UP, BSI and Traditional strategies, together with the percentage of hospitals giving an expected response for their claimed strategy, are shown in Table 8. Only 20 of 359 hospitals (5.6%) claiming UP had adopted the minimum set of policies expected under this strategy, and 0 of 50 claiming BSI had adopted all expected policies (Table 9). If a policy to educate staff was also required, then only 16 (4.5%) claiming UP adopted expected policies. If BSI was defined without the policy to relax handwashing when gloves were worn, then 1 1 of 50 (22%) met the requirements if an education policy was excluded but only 7 (14%) if education was required. The majority of Canadian hospitals had not adopted guidelines suggesting gloving as a substitute for handwashing, nor limitation of Universal Precautions to visibly—bloody body fluids (Table 7). A minority of hospitals claiming UP or BSI had eliminated special warning labels for specimens (UP 29%, BSI 36%) and for trash and linen (UP 32%, BSI 52%); correlation between adoption of these two policies was weak (r=0.10, p>0.50). The proportion of hospitals claiming adoption of UP and claiming a policy to train all health—care workers to use UP with all patients ranged from just over 50% in the smallest to 90% in the largest facilities. Page 20 Effectiveness of Infection Control Strategies Table 7: Adoption of Guidelines by Hospital Size BEDSIZE GROUP: Policy Guideline <25 25—49 50—99 100—199 200—299 300—499 500+ UP ends need for warning 13 20 28 26 6 26 15 labels on specimens. 16% 19% 27% 29% 12% 33% 30% Special labels & double bags 17 30 25 26 18 29 29 not required for waste or 21% 29% 24% 29% 36% 37% 58% soiled linen. Gloves replace handwashing 3 8 9 8 1 6 2 unless hands visibly soiled. 4% 8% 9% 9% 2% 8% 4% Private room required for 25 33 37 40 23 45 26 Staph pneumonia. 31% 32% 35% 45% 46% 57% 52%+ Private room not required 14 33 40 40 20 36 25 for Staph pneumonia. 18% 32% 38% 45% 40% 46% UP does not apply to many body substances unless they 8 23 33 32 23 37 24 contain visible blood. 10% 22% 31% 36% 46% 47% 48% Train all health—care workers 29 59 59 52 31 53 42 to use UP with all patients. 36% 57% 56% 58% 62% 67% 84% + Note: Total may exceed 100% as some hospitals claimed adoption of both. Page 21 Effectiveness of Infection Control Strategies Table 8: Percent (Number) of Hospitals Adopting Policies Expected under UP, BSI and Traditional Strategies EXPECTED RESPONSE UNDER: POLICY: UP BSI TRAD. No Special Warning Labels: ADOPT ADOPT REJECT —for Specimens 29% (107) 36% (18) 94% (138) —for Waste & Soiled Linen 32% (114) 56% (28) 78% (115) Gloves as Alternative to REJECT ADOPT REJECT Handwashing 93% (333) 10% ( 5) 96% (144) Private Room for Staph REJECT Pneumonia (n/a) 44% (22) (n/a) Precautions Don’t Apply to ADOPT REJECT REJECT Many Non—Bloody Body Fluids 43% (154) 90% (45) 86% (126) Note: CDC and LCDC guidelines are contradictory regarding Adoption or Rejection of requiring a private roan for Staph pneumonia under UP or Traditional strategies. As such, this policy is not applicable to assignment of UP or TRAD based upon policies adopted. Table 9: Infection Control Strategy Claimed versus Practiced STRATEGY STRATEGY PRACTICED: CLAIHED: UP BSI TRAD. OTHER TOTAL UP 20 1 119 219 359 (5.6%) BSI 0 0 14 36 50 (0.0%) TRADITIONAL 1 0 96 50 147 (65%) Total: 21 1 229 305 556 Page 22 Effectiveness of Infection Control Strategies Rationale for Adopting a New Strategy Hospitals explained their reason(s) in open text for adopting UP or BSI. and all reasons given were tabulated. These are summarized in Figure 1 as four categories. In all size groups, protection of staff was consistently the motivation most commonly claimed. Miscellaneous considerations (eg ‘common— sense approach’, “simpler change to introduce”, ‘acceptance by staff”, ‘want to keep isolation categories”, “eliminate prejudice against labelled patients’, etc.) and compliance with expert guidelines followed, with patient protection consistently the least common motivation. Figure 1: Hospitals’ Motivations for Adopting UP or BSI Page 23 Effectiveness of Infection Control Strategies Other Perceptions — Disposal of Sharps With regard to sharps disposal, only 13 of 556 hospitals (2.3%) described the use of cardboard disposal containers. All other descriptions referred to durable plastic (or, rarely, metal or glass) containers which were either obtained commercially or recycled from discarded solution containers. However, ICP’s in over half of the facilities claiming adoption of UP or BSI still felt that at least 50% of their staff members continued to recap used needles. While many reported advocating “safe” (one—handed or thimble) techniques when recapping cannot be avoided, several questioned whether these techniques were used in practice and none claimed any measurement of staff compliance. Table 10 summarizes how needles were transported from their point of use to disposal containers. In 46% of the hospitals, no special provisions were identified for needle recapping and transportation to disposal containers on medication carts or in utility rooms: nurses carried presumably unsheathed needles on any available tray or by hand (36.3%), or they recapped needles at the bedside (9.9%). 40% of the hospitals did advocate safety procedures or devices: 17.8% provided bedside containers to discourage recapping and 21.7% used special devices to improve the safety of recapping and/or transportation. Table 11 summarizes respondents’ perception of recapping practices in hospitals promoting strategies to discourage recapping: The alternative most commonly used was perceived to be the least effective. Overall, 318 respondents (57%) felt that at least half of their hospital’s staff recap used needles. Of these, 242 specified a strategy other than bedside containers to discourage unsafe recapping en route to disposal containers. 50 (21%) promoted recapping safety devices or one—handed technique, and, as noted in Table 11, 10 (4%) provided foam stabbing blocks and 9 (4%) provided special Page 24 Effectiveness of Infection Control Strategies Table 10: Predominant Method for Transporting Used Needles from the Point of Use to the Point of Disposal, by Hospital Size According to Number of Beds NUMBER OF BEDS: PREDOMINANT 25— 50— 100— 200— 300— METHOD <25 49 99 199 299 499 500 TOTAL Bedside Container 13.8* 13.6 12.4 15.7 26.0 25.3 28.0 17.8% Carry Unsheathed 36.3 50.5 40.0 41.6 32.0 13.9 30.0 36.3% Recap & Carry 23.8 9.7 10.5 9.0 2.0 6.3 2.0 9.9% Safe Recapping 5.0 4.9 11.4 18.0 18.0 15.2 14.0 11.7% Foam Stabbing Block 2.5 3.9 4.8 3.4 4.0 12.7 4.0 5.0% Special Trays 0.0 5.8 2.9 5.6 10.0 6.3 8.0 5.0% Not Specified 18.8 11.7 18.1 6.7 8.0 20.3 14.0 14.2% * Percent of size group using method indicated. Table 11: Perceived Effectiveness of Strategies To Avoid Recapping of Used Needles NUMBER (%) OF HOSPITALS CLAIMING 50% OF STAFF: PREDOMINANT DO NOT DO STRATEGY: RECAP RECAP Bedside Containers 61 (61.6%) 38 (38.4%) Carry unsheathed 83 (41.1) 119 (58.9) Foam Stabbing Block 18 (64.3) 10 (35.7) Special Trays 19 (67.9) 9 (32.1) PEARSON CHI-SQUARE = 17.550, 3 d.f., p < 0.001 Page 25 Effectiveness of Infection Control Strategies trays. Thus, only 29% of hospitals where the majority were perceived to recap had promoted point—of—use safety devices and procedures to reduce risk of needlestick injury. Other Perceptions — Knowledge of Costs and Benefits While this survey did not ask for detailed economic evaluations, only 19% of hospitals claiming UP or BSI indicated knowledge of cost implications in their institution. These were primarily gross estimates rather than sophisticated examination of marginal costs. Less than half a dozen sites indicated that they were planning or conducting comprehensive reviews. Measurement of compliance with infection control policies by health—care workers, and of benefits achieved under UP or BSI as practiced in Canadian hospitals, largely unknown at this time, were identified as priorities for further research. 57% of respondents indicated a desire to participate in the next part of this research: multicenter evaluation of compliance and effectiveness by standardized covert observations and questionnaires from health—care workers themselves. Summary of Major Findings 1. Three—quarters of Canadian acute—care hospitals reported use of UP or BSI. 2. Guidelines defining UP or BSI were not received by all of these hospitals: one—third of facilities under 200 beds (those most likely to need external help) had not received them. 3. While 65% of hospitals claiming a Traditional isolation program adopted all policies expected, <6% claiming UP or BSI adopted all expected policies. Inconsistency in the application of policy to different departments was noted, and numerous names other than UP or BSI were substituted. 4. Distinctions between UP and BSI, and the costs or benefits of either, were not well—known. Page 26 Effectiveness of fl2fection Control Strategies III. Have Hospital Staff Members Accepted the New Strategies? Infection Control Practices of Critical Care Nurses. The major emphasis in guidelines for UP or BSI focuses on appropriate use of gloves, handwashing and handling of sharps. Handwashing is a necessary24 but perhaps insufficient measure to protect patients and staff from nosocomial infection; UP and BSI guidelines therefore propose gloving as an adjunct. Frequent failure to wash hands, and the over—estimation of ones own handwashing compliance, remain common findings throughout studies spanning the last fifteen years.25 - 30 Failure to wear gloves for direct contact with blood or other body substances during nursing care is associated with transmission of herpes simplex3’ and hepatitis A32 viruses as well as a wide variety of bacteria,33 - and, rarely, hepatitis B39 and human immunodeficiency virus.40 41 Gloving, however, is not a panacea. Gloves contaminated after42 or even before use43 may spread contamination and infection.44 Some guidelines permit reuse of gloves between patients after effective washing, but washed gloves soon become sticky45 and even new gloves do not provide an absolute barrier to virus penetration.46 Bacterial contamination of hands has been demonstrated after dressing wounds even when gloves were worn.47 This could result from nasal carriage with subsequent transfer to hands, or from direct contamination of hands upon glove removal.48 Latex gloves may cause allergic reactions,49 and detrimental environmental byproducts are also generated in glove disposal.5° Current guidelines allow some individual discretion in choosing between no—touch technique and gloving with several of the patient—care practices selected for observation in this study. However, it is reasonable to conclude from current knowledge that universal use of gloves during all of the procedures selected might help to Page 27 Effectiveness of Infection Control Strategies prevent nosocomial infection of patients or staff. It is also reasonable to conclude from recent studies that glove use in many hospitals is far from universal. Needlestick injury is the foremost occupational exposure leading to hepatitis B infection among health—care workers. In the United States, it is estimated that 500 to 600 health—care workers will be hospitalized and over 200 will die from associated fulminant hepatitis, cirrhosis or liver cancer every year.15 A very small but real occupational risk of becoming infected by HIV also exists, and 70—90% of occupational exposures to this fatal infection have consistently involved needlestick injuries.41’ 51 - 61 Although it may be necessary to redesign invasive equipment in order to reduce this risk, UP and BSI infection control guidelines focus on admonishing health—care workers to handle needles carefully and especially to not recap them. This, however, is not new advice and there is little evidence to suggest that such warnings about safe handling of sharps have been effective.62 The few publications reporting understanding, compliance and/or effectiveness of UP or BSI in individual hospitals present contradictory findings. Programs may fail to achieve their objectives if they are based upon faulty theoretical models or if workers fail to comply with program policies. As described earlier, the majority of Canadian hospitals introduced myriad modifications in adopting UP or BSI, to a point where these names no longer have any specific meaning in practice. Further, the sharps disposal system most commonly provided to Canadian health—care workers was found to be the least effective in discouraging their recapping of used needles. It is not clear whether new infection control strategies have induced consistent use of gloves as expected, or whether safer sharps—handling practices have resulted. Page 28 Effectiveness of Infection Control Strategies Therefore, the next step in examining the effectiveness of UP and BSI as unifying strategies was to determine the extent to which health—care workers actually adhere to these precautions in daily practice. Materials and Methods: Recruitment and Participation Requirements All acute—care Canadian hospitals had received questionnaires during the administrative survey described in the previous chapter. In January and March 1990, letters inviting participation in this study were sent to administrators of hospitals that indicated in their response to the administrative survey a desire to take part in subsequent research. Participation requirements were explained as; (1) submission of hospital policies regarding gloving, sharps disposal, hepatitis B immunization and in—service education; (2) agreement to conduct 60 covert observations of nursing care in their critical care unit; (3) inspection of 10 filled sharps—disposal containers to estimate the extent of recapping; (4) review of staff needlestick incident reports; and (5) distribution of test questionnaires (described in the next chapter) to critical care nurses. ICPs in each participating site were asked to conduct 60 covert observations of specific nursing procedures in their intensive care unit (ICU). The quota of 60 observations requested from each site reflects a balance between a number low enough to be feasible yet high enough to provide precision and power. Sixty observations of nursing care would provide 99% power to detect 50% improvement over random (50%) compliance with approved procedures.63 Specific procedures monitored include intravascular therapy, wound care, oral care, and perineal care (Table 12). ICPs were instructed to record specific observations on a check—list every week over a period of several months, and each recorded observation was dated. ICPs also examined the Page 29 Effectiveness of Infection Control Strategies contents of 10 filled sharps disposal containers from the critical care unit, estimating the proportion of recapped needles as 0. 1—10%, 11—25%, 26—50%, or >50%. 10% and 25% were taken as two limits for tolerable policy compliance. Statistical Analysis and Hypothesis Testing Four observation scores were calculated for each hospital as the simple proportion of glove use in each of the four categories of procedures observed. These scores relate to hospitals, not individual nurses, as the sampling unit. Notch plots were used to examine the distribution of hospitals scores.64 Normality of score distributions was confirmed by the Kolmogorov—Smirnov test.65 SYSTAT (ver. 4.1) was used to perform these analyses. A null hypotheses (#3) that ICU nurses do not recap used needles was tested at two levels of compliance. Five or more containers with more than 10% of the needles recapped formed one critical region for rejecting the null hypothesis (a=0.0015, 130.0001 against an alternative hypothesis of 90% recapping). Six or more containers with more than 25% recapped formed the critical region for a second test (a0.0197, 13=0.0781 against an alternative of 75% recapping). Table 12: Nursing Care Procedures Observed INTRAVASCULAR ORAL Start new IV site Mouth care Change IV line Suction airway Use IV stopcock Retape endotracheal tube WOUND CARE PERINEAL Dress dry wound Perineal care Dress draining wound Remove bedpan Empty hemovac Empty foley bag Note: Form supplied to ICPs had 5 lines for recording observations of “Start new IV site”, 5 for “Change IV line”, etc., so that the 60 total observations would be composed of equal numbers from each of the four categories and that none of the procedures would be observed more than 5 times. Page 30 Effectiveness of Infection Control Strategies Results Response Rate 57% of over 500 hospitals participating in the administrative survey expressed interest in participating in this second phase, but only 72 actually enrolled. Half withdrew before completing covert observations and nurses’ tests, for the same stated reason that so few enrolled: workload conflicts of their ICP. The 35 hospitals completing this study were primarily large community—hospitals from urban centers across Canada. Approximately 3% of western, mid—western and central but 10% of eastern hospitals participated. Smaller facilities tended to be excluded by the requirement to make observations in a critical care unit, and very few university—affiliated hospitals elected to participate. Use of Gloves There was considerable variation from hospital to hospital in the frequency of glove use observed during various types of nursing care procedures: Figure 2 shows ranges of 0—100% in all of the categories observed. Distributions of overall hospital scores for glove use during IV and Perineal care procedures were approximately normal (p=0.679 and 0.272, respectively, Kolmogorov—Smirnov test). Oral and Wound care scores were skewed slightly more by relatively high numbers of hospitals observing frequent use, but were still reasonably normal in their distribution (p0.095 and 0.073 respectively). There were large positive correlations between several of these four categories of practice. Since the composition of observations from sites providing fewer than 60 observations varied, simple overall means would be confounded by the mix of procedures observed and therefore not be suitable for direct comparison. Direct standardization,66 applying the four category—specific rates to a “standard population” composed of 15 observations from each of the four categories, yields Page 31 Effectiveness of Infection Control Strategies uniformly—biased overall scores suitable for comparison (Figure 2). Figure 2: Frequency of Observed Glove Use During Types of Nursing Care 0 25% 50% 75% 100% Iv + WOUND ORAL PERINEAL 25% 50% 75% 10 % Note: Scale represents the percentage of observations in which gloves were worn. -. indicates the median among all 35 hospitals, () indicates a 95% confidence interval for the median, boxed areas extend from the 25th to the 75th percentile, * indicates an extreme value. “DS” is a uniformly—biased directly—standardized overall rate (see text). Handling of Used Disposable Needles As predicted in the administrative survey, nurses frequently did not comply with national guidelines for safe needle disposal. Table 13 summarizes the frequency with which sharps disposal containers held various proportions of recapped needles. Recommended disposal practices were followed 90% of the time in 9 of 32 hospitals (28%) and 75% of the time in 15 (47%). Page 32 Effectiveness of Infection Control Strategies Table 13: Frequency of Recapped Needles in Disposal Containers PERCENTAGE OF RECAPPED NEEDLES IN EACH CONTAINER 0% 1—10% 11—25% 26—50% 51—100% TOTAL CONTAINERS: 32 65 56 63 104 320 % OF TOTAL: 10.0 20.3 17.5 19.7 32.5 100% Summary of Major Findings 1. All surveyed hospitals had policies in place mandating use of protective apparel, but few were prepared to monitor policy compliance and provide feed—back on performance to their staffs. 2. On the average, gloves were worn about 60% of the time expected, with wide variation ranging from 0—100% among the hospitals. Fewer than half of the hospitals achieved minimally—acceptable compliance (75% usage). 3. Fewer than half of the hospitals achieved minimally—acceptable compliance (25% recapping) with policies to not recap used disposable needles. Page 33 Effectiveness of Infection Control Strategies Knowledge and Beliefs of Critical Care Nurses Programs may fail to achieve their objectives if they are based upon faulty theoretical models or if workers fail to comply with program policies. Direct observation of critical care nurses at work found frequent noncompliance with infection control policies. This could result from failure to know, to understand or to accept hospital policies. Unless pressures of the workplace interfere, strong correlation between knowledge and practice might be expected. However, industrial safety experience often shows discrepancies between knowledge and practice. In order to test the knowledge and beliefs of nurses whose work practices had been observed in the 35 hospitals described above, questionnaires were distributed to those nurses after completion of the covert observations. Materials and Methods: Test Forms Test statements covered knowledge and belief concerning risk recognition, risk control and infection control policy with respect to four knowledge areas: (1) hepatitis B and AIDS in the workplace, (2) safe handling of sharps, (3) use of gloves under UP or BSI, and (4) general aspects of infection control. Concepts and answers were taken from published infection control guidelines. Wording was modified after review of draft statements and their intended purpose by nurses experienced in infection control and patient care but not employed in the hospitals where the test would be applied. The test consisted of 32 statements, and responses were recorded on a 5—point scale of degree of (dis)agreement with each statement (a Likert scale). Some of the statements ask about personal history (e.g.: if the subject has suffered a needlestick injury in the preceding 30 days, if they had difficulty understanding the questionnaire or using an optional computer program provided). Each statement, an expected Page 34 Effectiveness of Infection Control Strategies answer consistent with corresponding referenced publication(s) and the pertinent reference(s) are listed in Appendix 3. Participating hospitals were offered printed forms or a computer program to conduct the tests. Statements were presented with identical wording on both the forms and computer screen. All critical care nurses in participating hospitals were invited by their own ICP to complete a standardized test anonymously at their own convenience; forms were collected a few days after mass distribution to minimize opportunities for collaboration. The interactive computer program, written in F0xBASE+ (version 2.00), does not ask for identity of individual nurses, but does automatically identify the hospital, type of computer, and test completion time. The encrypted and compiled program confirms integrity of stored coded responses before each subsequent use, and does not permit decoding by individual sites. Printed questionnaires, also anonymous, were returned in sealed envelopes. Upon receipt, they were marked with unique sequential numbers and transcribed using duplicate data entry via F0xBASE+ programs for automated error—checking and scoring. Statistical Analysis Four section scores (one for each of the knowledge areas tested) and an overall score were computed for each nurse as the percentage of statements answered as expected. Hospital scores were derived as the means of their nurses’ scores. The distribution of these scores was examined in several ways. Normality of nurses’ and hospitals’ overall and section score distributions were confirmed by the Kolmogorov—Smirnov test.65 Notch plots64 and ANOVA of nurses’ overall test scores (using site and claimed difficulty as independent variables) were used to determine whether nurses’ overall scores differed significantly between hospitals or in association with other variables. A bar Page 35 Effectiveness of Infection Control Strategies graph of the four section scores, grouped by site, was used to look for any nation—wide trends in relative performance among the different knowledge areas. Each concept on the questionnaire was tested by two statements which appear at variable distances apart from each other. Appendix 3 lists the pairings to which each statement was assigned (0 indicates unscored items). The influence of the order in which statements were presented was not studied; however, potential for learning bias as well as further examination of relative performance were explored by comparing scores on the first versus second statement in each pair using Tukey’s sum—difference graph.67 Correlation coefficients were also computed. A null hypothesis (#4) that there is not a strong positive correlation (r0.5) between infection control knowledge and daily practice scores was tested in three ways: correlation coefficients between individual knowledge and practice component section scores, between unweighted overall test and observed—practice summary scores, and also with weightings derived from canonical correlation using the four knowledge sections of the test arid four care categories of the observations. Canonical correlation is a multivariate technique to produce linear combinations attaining the maximum correlation possible.68 SYSTAT (ver. 4.1) and SAS (ver. 6.03, PROC GLM) were used for these analyses. Results Response Rates None of the sites used the interactive software. Seventy—two of 489 questionnaires received from 35 sites had one or more questions left unanswered; eight of these (from eight different sites) left an entire page blank and were excluded as incomplete. Table 14 summarizes characteristics of participating hospitals completing this part of the study. Page 36 Effectiveness of Infection Control Strategies Table 14: Characteristics of Participating Hospitals Approx. Site Number Region Questionnaire of Beds of Canada Response Fraction 61 200 West 7/10 (70%) 125 200 West 15/16 (94%) 123 300 West 5/16 (31%) 9 350 West 7/17 (41%) 417 450 West 9/14 (64%) 257 >500 West 8/27 (30%) 258 >500 West 30/67 (45%) 19 250 Mid—West 6/30 (20%) 103 400 Mid—West 11/29 (38%) 225 400 Mid—West 11/50 (22%) 420 400 Mid—West 13/22 (59%) 527 >500 Mid—West 47/65 (72%) 131 50 Central 3/ 6 (50%) 78 100 Central 7/10 (70%) 192 100 Central 6/12 (50%) 95 235 Central 10/15 (67%) 165 250 Central 13/20 (65%) 408 400 Central 20/30 (67%) 481 400 Central 23/50 (46%) 541 400 Central 21/61 (34%) 81 >500 Central 22/59 (37%) 104 >500 Central 29/60 (48%) 179 >500 Central 19/40 (48%) 67 100 East 5/ 6 (83%) 378 100 East 10/25 (40%) 296 100 East 6/14 (43%) 6 200 East 13/24 (54%) 59 200 East 9/18 (50%) 189 200 East 14/16 (88%) 363 200 East 15/15 (100%) 418 250 East 13/25 (52%) 285 300 East 15/17 (88%) 284 400 East 10/15 (67%) 558 450 East 15/40 (38%) 452 >500 East 19/29 (66%) Note: Response fractions are the number of ICU nurses returning a completed questionnaire divided by the number of ICU nurses in each hospital. Page 37 Effectiveness of Infection Control Strategies Nurses’ Knowledge and Belief Scores Test scores by section tended to range from highest to lowest for sharps handling, gloving, AIDS or hepatitis, and general aspects of infection control, respectively (Table 15). The proportion of nurses in each hospital agreeing that their hospital’s infection control measures were practical, effective and well— documented is shown in Figure 3, as well as the proportion claiming receipt of instruction in these policies. There was a statistically significant association between nurses agreeing with their hospitals policies and claiming receipt of instruction (p<O.OOl, chi—square test; Pearson correlation coefficient O.2) but no such association between the proportion of nurses in agreement with policies or receipt of instruction and higher overall hospital test or observed—practice scores. Inservice education provided to these nurses appeared to stress sharps handling more frequently than gloving or general aspects of UP/BSI. Table 15: Relative Ranking of Knowledge Test Section Scores Number of Hospitals in Which Section Score Was Ranked As: Test Section Highest 2nd 3rd Lowest SHARPS 24 9 2 0 GLOVES 11 24 0 0 AIDS/HEPATITIS 0 2 29 4 GENERAL 0 0 4 31 Nurses’ scores did not improve as a function of exposure to test questions. Figure 4 depicts the distribution of scores for question—pairs horizontally, and for discordance within pairs vertically. The frequency of correct answers to a second member in each pair of questions exceeded that for the first member in only three of eleven pairs. 42—52% of answer—pairs were discordant (one correct, the other incorrect) for all pairs except those regarding philosophic Page 38 Effectiveness of Infection Control Strategies Figure 3: Effectiveness of Hospitals’ In—Service Program 0.00 0.50 1.00 I(+ Proportion of nurses agreeing that their hospital’s policies are practical, effective and well—documented. F Proportion of nurses claiming receipt of in—service instruction within past year re: Universal Precautions + 1 Proportion of nurses claiming receipt of in—service instruction within past year re: sharps handling Proportion of nurses claiming receipt of in—service instruction within past year re: proper use of gloves 0.00 0.50 1.00 Note: Scale represents the proportion of nurses in each hospital responded affirmatively. + indicates the median among all 35 hospitals, () indicates a 95% confidence interval for the median, the boxed area extends from the 25th to the 75th percentile, * indicates an extreme value. Page 39 Effectiveness of Infection Control Strategies Figure 4: Tukey Sum—Difference Graph of Correct Response Frequencies 300 Difference F I Between 200 Correct 3 Answer Frequency 100 B for K A Paired C E Questions 0 D G —100 H —200 0 200 400 600 800 1000 Sum of Correct—Answer Frequency for Paired Questions LEGEND: Net discordance in paired—item scores is indicated by distance above or below the dashed horizontal line; pairs with higher scores appear to the right and with lower scores to the left on this graph. Questions were paired on the basis of testing related concepts: A = infectivity of HIV and hepatitis B virus (questions 1 & 5) B = need for screening and warning labels (questions 2 & 26) C = purpose and philosophic differences of UP/BSI (questions 4 & 30) D = immunity to infectious disease (questions 6 & 24) E = operational definitions with UP and BSI (questions 8 & 18) F = frequency and severity of needlestick injury (questions 9 & 12) G = recapping and need].estick risk (questions 10 & 13) H = protection afforded by gloves (questions 15 & 19) I = frequency of handwashing (questions 16 & 23) 3 = proper use of gloves (questions 20 & 22) K = definition and disposal of infectious waste (questions 27 & 28) Page 40 Effectiveness of Infection Control Strategies differences of UP and BSI (C, 29%), recapping and needlestick risk (G, 23%) and infectious waste (K, 22%). Scores were lowest on questions regarding infectious waste, those pertaining to quantification of risk (F), and purpose or philosophy of specific control measures. Highest scores were achieved on information recognized well before the advent of new infection control strategies (D,G,I,J). There were statistically significant differences between scores achieved by nurses in individual hospitals as well as by those claiming difficulty versus no difficulty understanding the test (2—way ANOVA): DEGREES OF TYPE III SUM ME?N F SOURCE FREEDC1 OF SJ?iRES SQUARE RATIO p Hospital 34 12763.08693 375.3849 2.85 0.0001 Difficulty 1 688.93145 688.93145 5.22 0.0228 Neither region nor hospital size were significant in explaining this variation about a total mean score of 54%. and very few sites (e.g.: site #6) had a distinctly different median score (Figure 5). The 141 nurses (29%) claiming difficulty with the test itself achieved a slightly lower median score than those not claiming difficulty (Figure 6). Similarly, those claiming receipt of in—service education or agreeing that their hospital’s infection control measures were practical, effective and well—documented achieved only slightly higher scores than those not. Overall scores achieved by nurses approximated a normal distribution (p0.05, Kolmogorov—Smirnov test) in 30 of the 35 hospitals. The hospitals’ overall knowledge test scores were normally distributed (p0.3l6, Kolmogorov—Smirnov test), but their directly standardized overall practice scores less so (p=0.046). Weighted arcsine transformation of these scores [fniarcsineVpi)] adjusted the raw scores (p1) for differing numbers of tests or observations submitted by each hospital (fli) as well as modifying the distribution shape of overall test and practice scores (p0.1l4 and 0.185 respectively, Kolmogorov—Smirnov test). The Pearson correlation coefficient Page 41 Effectiveness of Infection Control Strategies Figure 5: Nurses’ Overall Test Score, by Site (Ordered by Region and Size) MINIMUM SCORE MAXIMUM SCORE 23.0% 50.0% 100.0% Site # 61 9 .__________.____I1J—) 417 __ ____ 257 ( ) [ 258 N 19 D -f 103 S 225 * 420 ( .f) 527 Page 42 Effectiveness of Infection Control Strategies Figure 5 (emit.): MINIMUM SCORE MAXIMUM SCORE 23.0% 50.0% 100.0% Site # F F 192 -(- 95 165 ( -f ) 408( ..F ) 481 * 541 _ 81 104 -f ) 179 Page 43 Effectiveness of Infection Control Strategies Figure 5 (cont.): MINIMUM SCORE MAXIMUM SCORE 23.0% 500% 100.0% Site # * ____ ‘1 3:: 296 C ( __ 6 A I H + F 189 363 418 285 284 -F 1 558 ________ * 452 Legend: j- indicates medians, () indicates 95% confidence intervals, and * indicates extreme values. Median scores differ significantly if their confidence intervals do not overlap. Page 44 Effectiveness of Infection Control Strategies Figure 6: Nurses* Overall Test Score, by Personal Bistory Claims MINIMUM SCORE MAXIMUM SCORE Claim 23.0% 50.0% 100.0% _____ No Difficulty Difficulty -1-) * Understanding Questionnaire In—Service * _________________ ( _________________ * * * Not Received In—Service * * I c-I-> * Received Not Satisfied * I (..f ) __ _ * with Policies T (..[ ) I Satisfied withI I Policies Legend: -- indicates median score for all nurses regardless of hospital, 0 indicates 95% confidence intervals, and * indicates extreme values. Median scores differ significantly if their confidence intervals do not overlap. Box width is proportional to the square root of the group size. Page 45 Effectiveness of Infection Control Strategies between these summary scores was only moderately strong (zO.35) and just achieved statistical significance (p0.04). Spearman’s correlation coefficients among test section and care category scores were not statistically significant (Table 16). Table 16A treats all hospitals as equals; 16B (the transformed data) gives greater weight to those with larger nursing staffs (as implied by larger numbers of tests returned). The number of multiple comparisons possible in Table 16 inflates the probability that a spurious association may be found as statistically significant; Bonferroni adjustment reduces the chances of this. Relationship Between Knowledge and Practice Correlation between directly—standardized overall practice and knowledge scores was not statistically significant (Table 16), nor were any of the larger correlations achievable through reweighting by coefficients derived from canonical correlation analysis (Table 17). Further, if the analysis is restricted to those sites coming closest to the number of observations requested, a persistent negative trend in the correlation coefficient is evident (Figure 7). At the extreme of this sensitivity analysis, data from the four sites providing all 60 observations requested yield a correlation coefficient of —0.8. This effect is also evident in the difference between test—practice correlation coefficients on Tables 16A and 16B: weighted—arcsine transformed data provides a correction for this confounding and yields a smaller correlation coefficient. Summary of Major Findings 1. In half of the hospitals, no more than 50% of participating nurses agreed that their policies were practical, effective and well—documented. 2. Many nurses held divergent opinions, did not understand or did not agree with tenets fundamental to UP and BSI. Test scores averaged 54% correct. 3. A positive correlation between knowledge and practice was not found. Page 46 Effectiveness of Infection Control Strategies Table 16: Spearman Correlation Coefficients Between Test and Practice Scores Table 16A: Correlation Coefficients, Raw Data OVERAlL TEST PRACTICE AIDS/IP SHARPS GLOVES OTHER IV WOUND ORAL PERINEAL Overall TEST 1.000 PRACTICE 0.310 1.000 Test Section AIDS/HEP 0.783 0.275 1.000 SHARPS 0.438 —0.061 0.231 1.000 GLOVES 0.709 0.246 0.401 0.142 1.000 C7l’HFR 0.586 0.363 0.277 0.002 0.332 1.000 Care Category IV 0.432 0.688 0.298 0.008 0.341 0.503 1.000 WOUND 0.267 0.757 0.191 0.089 0.075 0.370 0.501 1.000 ORAL 0.145 0.665 0.184 —0.263 0.308 0.087 0.245 0.315 1.000 PERINEAL 0.192 0.800 0.201 0.077 0.072 0.172 0.420 0.492 0.500 1.000 Table 1GB: Correlation Coefficients, Weighted Arcsirie Transfornd Data OVERALL TEST PRACTICE AIDS/HEP SHARPS GLOVES C1I’HER IV WOUND ORAL PEPJ]EAL TEST 1.000 PRACTICE 0.287 1.000 AIDS/HEP 0.932 0.236 1.000 SHARPS 0.908 0.250 0.811 1.000 GLOVES 0.980 0.259 0.901 0.872 1.000 OTHER 0.967 0.309 0.879 0.860 0.938 1.000 IV 0.259 0.756 0.245 0.187 0.237 0.310 1.000 WOUND 0.207 0.913 0.154 0.206 0.168 0.254 0.682 1.000 ORAL 0.280 0.674 0.256 0.147 0.301 0.272 0.317 0.575 1.000 PERINEAL 0.166 0.857 0.168 0.157 0.131 0.180 0.557 0.731 0.622 1.000 Note: Values 0. 341 are statistically significant (p0 .05, 2—sided) without Bonferroni adjustment; values 0.573 achieve statistical significance with Bonferroni adjustment.69 The latter are shown boldface. Page 47 Effectiveness of Infection Control Strategies Table 17: Canonical Variate Coefficients and Correlations KNOWLEDGE TEST SECTION SCORES: OBSERVED PRACTICE SCORES: AIDS/HEP SHARPS GLOVES OTHER rl* IV WOUND ORAL PERINEAL 0.124 —0.577 0.535 0.519 0.593 —0.703 0.147 —0.804 0.398 0.122 0.597 —0.453 0.738 0.409 0.254 0.804 —0.664 0.245 *Note: None of the canonical correlations are statistically significant (p>0.3) Figure 7: Spearman’s Correlation Coefficient (of Knowledge and Practice Scores) vs. l4inumum Number of Practice Observations Required for Inclusion in Analysis I I I 0.5 CORRELATION COEFFICIENT . I I I . 0.0 U —0.5 I —1.0 I I I I I 0 10 20 30 40 50 60 [34) [33] [30] [26] [22) [14] [4] MINIMUM NUMBER OF OBSERVATIONS REQUIRED Note: Numbers in brackets indicate number of sites included. Page 48 Effectiveness of Infection Control Strategies IV. Have New Infection Control Strategies Reduced Infection Risks? Although reduced infection risk for patients will undoubtedly provide the major economic benefit from an effective infection control strategy, reduced risk for health—care workers was the major focus of this research for two reasons. First, Canadian hospitals indicated that protection of staff, specifically from HIV. was their primary motivation for adopting new strategies. This can be evaluated indirectly by measuring needlestick injury rates, since the majority of occupational HIV and hepatitis B infections involve needlesticks. Second, there were too many interacting variables associated with most types of nosocomial infections suffered by patients, too many endogenous and exogenous sources of pathogens and too many inadequacies in current microbiologic typing methods to make a study of patients’ risk practicable. The impact of nurses’ gloving practices on intravascular—associated nosocomial infections was considered for study, since this problem involves relatively few confounding variables. However, an adequate typing method was not available for the nosocomial pathogens most commonly associated with intravascular cannulae, coagulase— negative staphylococci.16 Epidemiologic Assessment of Risk to Hospital Staff— Needlestick Injuries Needlestick injury is a well—recognized occupational hazard for health—care workers. Published guidelines discourage recapping of used needles as an unsafe and unnecessary practice. However, the strategy most commonly employed by Canadian hospitals appeared to be the least effective in discouraging recapping of used needles (Tables 10 and 11). Subsequent observation of nursing practice confirmed the opinion that many nurses still recap used needles in spite of policies discouraging this habit. A test of knowledge among these same nurses confirmed that most agree that used needles should not be recapped. However, Page 49 Effectiveness of Infection Control Strategies these were cross—sectional surveys, not before—and—after studies. Therefore, the next step in this research was refinement to see if adoption of UP or BSI resulted in decreased needle recapping or injury rates. Needlestick injury incidence rates were estimated from data before and after adoption of new infection control strategies, and incidence density rates were calculated (essentially, number of injuries divided by number of hours worked) on paired before—and—after data. Incidence density is more meaningful than other attack rates which are often published (e.g.: injuries per number of employees, per number of full—time equivalent employees, or per number of hospital beds) because it takes the duration of risk—exposure into account.7° Materials and Methods: The nursing test questionnaire described above asked whether respondents had suffered one or more needlestick injuries in the preceding thirty—day period. ICPs reviewed the hospital’s employee health records after nurses completed the questionnaires, looking for needlestick injury reports from critical care nurses during three consecutive preceding thirty—day periods and during corresponding thirty—day periods prior to adoption of their new infection control strategy. In order to control for the confounding influence of differing durations of exposure to a risk of needlestick injury, incidence density was calculated by dividing the number of needlestick injuries reported among critical care nurses by the number of hours those nurses worked in each thirty—day period. Paired analysis of before versus after UP/BSI rates was used to control for differing baseline rates among the hospitals. The Sign Test for persistence of a trend of any magnitude, and Wilcoxon’s Signed Ranks Test for a trend of significant magnitude were used.71 SYSTAT (ver. 4.1) was used for these tests. The frequency of reported injuries was compared to the number of questionnaire— Page 50 Effectiveness of Infection Control Strategies respondents claiming needlestick injury in order to assess the extent of injury under—reporting. Results Eleven hospitals provided complete data (number of needlesticks reported and hours worked among critical care nurses for three 30—day periods after and three corresponding periods before adoption of UP or BSI). Thirty—three hospitals provided partial data. Eleven of 312 staff (3.5%) who returned questionnaires in hospitals providing complete data claimed one or more needlestick injuries during a preceding thirty day period; only four needlestick injuries were documented in incident reports. This rate is higher than the 2.3% (21 injuries among 929 staff in a 30—day period) documented in employee health records of all responding hospitals. Monthly incidence density rates in the eleven hospitals providing complete data ranged from a minimum of 0 per 1000 hours worked to maximums of 3.94 before and 0.41 after UP/BSI adoption. Although the latter numbers suggest lower risk after each hospital adopted a new infection control strategy, paired data did not show a statistically significant trend based upon persistence of differences of any size (p=0.332, Sign Test). If the magnitude as well as direction of before— versus after—UP/BSI differences were considered, borderline statistical significance was attained (p=0.076, Wilcoxon Signed Ranks Test). Much of’ the latter effect was attributable to one hospital with a before—UP/BSI incidence rate at least one order of magnitude higher than any of the other hospitals (Figure 8). The proportion of discarded needles that were recapped had also been assessed in ten of these eleven hospitals. Only four showed evidence of 25% recapping frequency, and decreasing needlestick incidence rates were found in Page 51 Effectiveness of Infection Control Strategies only one of these. Conversely, four of six hospitals where recapping was still widespread reported decreased post—UP/BSI incidence rates. Figure 8: Needlestick Injury Rates in 11 Hospitals Providing Paired Data INJURY RATE 4 Needlesticks per 1,000 hours worked 3 2 1 0 Note: Hospital “A” had pre—UP/BSI rates one order of magnitude higher than the other ten hospitals. Distinct data points are labelled by hospital (A,B,C,K); * indicates overlapping data points from two or more hospitals in this time—series analysis. Summary of Major Findings 1. Employee health records documented fewer nurses suffering needlestick injury during a 30—day period (2.3% of 929 nurses in 33 hospitals) than was found by surveying nurses directly (3.5% of 312 nurses in 11 hospitals). 2. Only 1 of 11 hospitals indicated appreciable risk reduction after UP started. 3. An association between reduced needle—recapping and reduced needlestick injury risk was not evident. —90 —60 —30 0 30 60 90 Pre—UP/BSI Days Post—UP/BSI Days ERA Page 52 Effectiveness of Infection Control Strategies Epidemiologic Assessment of Risk to Hospital Patients— Tracing the Sources of Infection by Microbiologic Methods The marginal cost of UP in excess of existing infection control costs is appreciable,72 and its cost per case of occupational HIV seroconversion prevented has been estimated at over $8—million.73 While patients and staff members have a right to a safe hospital environment, and hospitals, in turn, have both legal and ethical obligations to provide this, it is unlikely that economic benefits from UP will exceed its costs. Accurate cost—effectiveness comparison of UP, BSI and other strategies will undoubtedly require assessment of their impact on the costs associated with patients’ nosocomial infections. If treatment costs can be averted by preventive measures, this would motivate implementation and support of those measures. However, in order to classify patients into case or referent study groups for such epidemiologic and economic research, better microbiologic typing methods are needed. Microbiologic methods to determine whether isolates are epidemiologically related exploit the diversity within taxonomic relationships. If one or more differences can be found, this implies that isolates may be unrelated in spite of their common genus—species name. Typing to a subspecies level supports epidemiologic investigation by determining whether microbes isolated from two sources may have an epidemiologic relationship (e.g.: from different patients, suggesting cross—infection; from patients and an environmental reservoir, suggesting common—source transmission; from different sites of a patient, such as blood and an intravascular cannula, suggesting routes of transmission, etc.). However, the problem of proving epidemiologic relatedness by microbiologic typing is often analogous to hitting a moving target with tools of undefined precision, accuracy and reliability.16 Page 53 Effectiveness of Infection Control Strategies The extent of diversity within a species must be documented and sufficient to generate enough typing categories for adequate discriminatory power. The typing method itself must be sufficiently precise, accurate, reliable and practical to generate useful results. Methods that have been or could be applied to typing coagulase—negative staphylococci were reviewed16 (Table 18). The MIDI system for semi—automated fatty acid analysis (Microbial ID, Inc. Newark Delaware) was felt to show promise, and an evaluation project was initiated. That research is still in progress (see Appendix 4). Table 18: ypiug Methods for Coagulase-Negative Staphylococci KEY: + = Good ± = Problematic, but possible — = Inadequate Elect. = Electrophoresis REA = Restriction Endonuclease Analysis RFLP = Restriction Fragment-Length Polymorphism Fatty Acids = Fatty Acid Profile CRITERION Biotype and/or ntibiogram Phage CONVENTIONMJ METHODS NOLECULAR METHODS NOVEL METHODS Serology Plasmid Profile Chromosomal Multilocus Fatty Elect. REA RFIAP REA RFLP Enzyme Elect. Acids 1. CIiN IT DO THE JOB? Discriminatory ± — — ± + + + + ? Power Species Diversity + — — — — — — — — Documented 2. DOES IT DO THE JOB? Accuracy and Reliability ± ± - ÷ + + + + ? Availability + — — ± — — — — Page 54 Effectiveness of Infection Control Strategies V. Discussion: Validity, Reliability, Power and Generalization of’ This Research This research produced a considerable amount of data to address three basic questions: Have Canadian acute—care hospitals adopted Universal Precautions or Body Substance Isolation; do their staff members use the new system of precautions in daily practice; and has reliable use of a new system led to decreased risk of infection? In order to answer these questions and understand the limits to interpretation in those answers, a basic procedure for appraisal of data is important. Abramson suggests that this involves three steps.74 First, what are the facts, how were they obtained and what is the likelihood that bias has distorted the true facts? Second, what are the possible explanations (i.e.: a fluke of random chance, confounding or a true relationship)? Third, what additional information is required to confirm the possible relationship(s)? This chapter reviews the methods and data presented earlier in order to appraise the information derived from them. Administrative Survey In the administrative—level survey, most Canadian acute—care hospitals reported adopting Universal Precautions or Body Substance isolation. As in all evaluative research, validity and reliability are critical issues. Face and content validity of survey questionnaires were high in that questions concerning discrete, objective key variables related to stated survey objectives. Consensual validity was established by pretesting survey forms at ten geographically diverse pilot sites and discussing these preliminary results with an expert research supervisory committee. Reliability was supported by using an objective mailed survey (allowing respondents to check institutional records before answering, and reducing a risk of interviewer bias); including redundant Page 55 Effectiveness of Infection Control Strategies questions to ensure consistency of response; automating error—checking on data entry; and random checks of questionnaire data against corresponding computer— stored transcripts. Other than redundant questions, there was no way to confirm responses in this phase of the research. However, given the anonymous nature of the survey, there was no obvious motive for respondents to misrepresent their hospital’s position and the nature of responses does not suggest that unduly favorable pictures were provided. Further, copies of policies received from hospitals participating in the second phase of the research confirmed their administrative survey claims. The nature of responses received both in the pretest and main survey were clear and did not suggest misunderstanding of questions themselves. The questionnaire was created in English, then translated into French by one native—speaker, checked by a second, and my translation of completed French forms was double—checked by a third person whose native language was French. Neither misrepresentations nor misunderstandings in completing or interpreting the questionnaires were likely to have distorted the conclusions drawn. Non—response and self—selection bias weaken the survey’s external validity; however, use of a sampling frame and separate analysis of responders to a second mailing indicated that non—responders were primarily small, rural hospitals with guideline receipt rates lower than responders. Highly conservative correction for nonresponse was therefore unwarranted. Given the direction of bias, survey results were unlikely to have under—estimated guideline receipt or adoption rates. The first two null hypotheses tested were rejected: statistically significant associations were found between hospital size, preferred infection control system and receipt of pertinent guidelines. Rejection of a null hypothesis carries the Page 56 Effectiveness of Infection Control Strategies risk of a—error, a chance that aberrant findings resulted from a quirk of random chance. However, corroborating evidence reduces this possibility here. Beyond the level of statistical significance achieved, parallel trends were observed, for example, in adoption rates for both UP and BSI as opposed to a Traditional system, and in receipt rates for a variety of different publications. The stratified and multivariate analyses performed explored any influence of the most likely confounding variables which might have distorted true relationships. Other variables examined were ICP—to—bed ratio, provision of risk services (e.g.: dialysis, drug abuse or sexually transmitted disease clinic), hospital location, and size as an interval variable using number of beds, group median or log of group median. Hospital size remained the most significant determinant of information receipt in models that considered all of these variables simultaneously. Objective comparison of the specific policies adopted versus the system claimed provided important additional information about the infection control systems of these hospitals. Increasing hospital size and presence of ICPs or medical teaching programs may indicate a more cosmopolitan outlook, and thus greater emphasis on staying informed. It is unlikely that smaller hospitals simply felt that UP or BSI and the underlying problem of HIV were not relevant to them: nearly half of the smallest hospitals claimed to have adopted UP, stated motivations for adoption were the same in hospitals from all size ranges, provision of risk—services was not found to be a significant variable, and trends related to size were evident throughout the entire range of hospital size groups. Some hospitals undoubtedly accepted the UP or BSI system but rejected certain guideline recommendations selectively after careful review, but this does not explain all of the deviation from expected policies found. The proportion of Page 57 Effectiveness of Infection Control Strategies hospitals that had not received guidelines defining the system they claimed, the low correlation between use of “biohazard’ labels for housekeeping versus laboratory materials, the few sites commenting upon a major discrepancy (a typographical error) between two guidelines, and the comments received suggest other explanations for this deviation. Covert Observation of Nursing Practice In the study of nurses’ daily practices, covert observation found significant variation in staff members’ adherence to their hospital’s system of precautions. Validation of observation accuracy and inter—observer agreement for different hospitals’ ICPs could not be evaluated. These are weaknesses in the internal validity of this research. ICPs, however, routinely observe and evaluate aseptic practices as one of their own job responsibilities. Observations required in this study were objective: gloves were worn or not, and needles were capped or not. The open layout of most ICU’s promotes relatively unrestricted view of any nursing procedures being observed. These factors hopefully reduced observer biases. ICPs were recruited for the study because they are trained observers of aseptic practice who regularly visit all nursing units, and therefore may not raise nurses’ suspicion or prompt major changes in work practices simply by their presence. ICPs were instructed as to what kinds of practices to observe, and to spread their observations of glove use over several months in order to obtain results representative of nursing unit practices. Extended duration of studies may introduce problems (e.g.: drop—outs, consistency of performance, temporal effects), but in this case an observation period of several months was necessary. When ICPs evaluated the frequency of needle—recapping, no effort was made to distinguish between needles used solely to draw up medications versus those exposed to patients’ blood. Page 58 Effectiveness of Infection Control Strategies In addition to self—evident descriptive data on glove use, a third null hypothesis regarding the unsafe practice of needle recapping was rejected in 53% of these highly—motivated hospitals. The probability that significantly worse compliance with needle disposal policies really existed but was not found (13— error) was low, zO.08 in each site at a sample size of 10 units (Table 19). Table 19: Magnitude of a— and a—error for Hypothesis #3 Number of Containers Probability if True With >25% of Needles Recapping Rate Is Nagnitude of Action Recapped 25% 75% a 13 Accept 0 0.0563 0.0000 0.0000 Null 1 0.1877 0.0000 0.0000 Hypothesis 2 0.2816 0.0004 0.0004 3 0.2503 0.0031 0.0035 4 0.1460 0.0162 0.0197 5 0.0584 0.0584 0.0781 Reject 6 0.0162 0.1460 0.0197 Null 7 0.0031 0.2503 0.0035 Hypothesis 8 0.0004 0.2816 0.0004 9 0.0000 0.1877 0.0000 10 0.0000 0.0563 0.0000 Staff members’ use of prescribed infection control precautions in daily practice was far from universal, and this trend was evident in many hospitals with both gloving for various types of care as well as needle disposal practices. This is consistent with reports in the recent literature and the historic reports of noncompliance under traditional programs which prompted development of new infection control strategies in the first place. Test of Nurses’ Infection Control Knowledge and Beliefs A test of knowledge and belief found that many nurses in all parts of the country held views divergent from published information. Efforts to safeguard internal validity in the knowledge and belief test phase of this research were Page 59 Effectiveness of Infection Control Strategies similar to efforts in the administrative survey. Face and content validity of questionnaires were high in that questions related to stated objectives and were derived from key publications. Consensual validity was established by pretesting question statements and discussing their intent with an independent panel of experts in infection control and nursing practice as well as with an expert research supervisory committee. Two questions were selected for each concept tested. Again, the questionnaire was created in English, then translated into French by one native—speaker and checked independently by a second. Finally, the 35 ICPs acting as liaison to their hospital were invited to comment on any concerns about ambiguity or validity. Automated error—checking on data entry, automated scoring and random comparisons of questionnaire data with corresponding computer—stored transcripts again were used to guard against introducing transcription errors in data handling. Few sites produced significantly different mean test scores (Figure 5). Confounding of mean scores by attitude toward policies, receipt of instruction or difficulty with the test (Figure 6) was not significant (Figure 9). Score distributions tended to approximate a normal distribution. The Kolmogorov— Smirnov test used is relatively powerful for detecting non—normality in small samples.75 The few deviations that it detected were not severe (Figure 10). Two—way ANOVA indicated site and claimed difficulty as determinants of test score; significance of differences found was confirmed by nonparametric methods. There are two aspects to reliability in psychometric testing: internal consistency and stability. Internal consistency, that is, cohesiveness among test items themselves, is best measured by Kuder—Richardson’s formula KR2O or KR2176 which are special cases of Cronbachs alpha coefficient. Stability provides an indication of the degree to which achieved scores on a test measure Page 60 Effectiveness of Infection Control Strategies Figure 9: Magnitude of Confounding in Nurses’ Test Scores —30 —15 0 15 30 * _____ * Difficulty Understanding Test H Agreement With Hospital Policies * * ———L:if] * * Receipt of Inservice Education —30 —15 0 15 30 Note: Scale represents the difference (in percentage points) between mean scores for nurses in each hospital who claimed or did not claim each factor. + represents median differences among the 35 hospitals. () represents 95% confidence intervals for medians. * represents extreme values. These values are corrected for differences in individual hospital’s scores. individuals’ “true” scores. It may be assessed by giving the same test to each subject twice (test—retest method) or using another, equivalent second test (parallel forms), or by correlating scores achieved on each of several equivalent parts of a single test given once to each subject (split—half method). Internal consistency among the diverse items in a nurses’ knowledge and beliefs test developed for this research was expected to be low, and therefore was of little interest. Stability of the new test, as an indication that similar scores would be achieved if nurses were tested repeatedly, was difficult to measure but of greater interest. Page 61 Effectiveness of Infection Control Strategies Figure 10: Normal Probability Plot— Distribution Rejected by the Kolmogorov—Smirnov Test Expected 3 I I Value B 2 (Standard 2 Deviations • 2 fromthe 1 3 2 Mean) 3 2 4 2 0 4 3 5 5 —1 3 2 -2 —3 I I I 20 30 40 50 60 70 80 Overall Test Score (% Correct) I I 0.4 . • B Deviation B B from . • Expected 0.2 . • • Value B • • • . • B I B • . I I 0.0. I B B B I I B B B B I B B B B • B B B --0.2 • B B B —0.4 I 1 I Note: Normality of the distribution of these 47 nurses’ test scores from site #527 was rejected by the Kolmogorov—Smirnov test (p=0.008). Of fifty—five distributions tested, this was one of the more extreme p—values among nine rejected. There were more scores near the middle of the distribution than expected, but the extent of this deviation was not severe. Page 62 Effectiveness of Infection Control Strategies Each ICU nurse could not be tested on two occasions for a test—retest or parallel—forms assessment, a simple split—half single—test method would require too many randomizations to provide statistically valid results,76 and a standard method to assess stability would be difficult to establish for tests consisting of nonequivalent items. Therefore, reliability of the nurses’ knowledge test was assessed in the following manner. Phi coefficients77 (a correlation coefficient for two dichotomous variables) were computed for each of the eleven pairs of questions for each site returning at least ten completed tests (Figure 11). Questions had been paired on the basis of similar concept. Appendix 3 lists the questions and their pairings; 0 indicates unscored items. The median of each site’s eleven phi values then was taken as an index for that site. Median phi values were corrected for test length with the Spearman—Brown formula77 (“stepped—up reliability”). These stepped—up medians then were used in meta— analysis78 to determine whether a statistically—significant positive correlation was characteristic of all of the sites. That consistency would suggest a degree of reliability, indicating that the new test may provide a reproducible measurement. Meta—analysis of phi coefficients reexpressed by Fisher’s z—transformation failed to find significant differences among the sites (p>0.99, chi—square test for heterogeneity). This suggested that all sites shared a common correlation value, estimated as r0.l4, 95% confidence interval O.03—O.25. This weak but statistically significant positive correlation between paired—responses provides weak evidence of test reliability. That conclusion was supported by finding correlations among the four knowledge section scores all to be positive (Table 16). The frequency of discordance found in responses to question pairs suggests that many of the paired questions were not of equivalent difficulty. This limits the ability to explore test reliability from these data. Paired questions appear Page 63 Effectiveness of Infection Control Strategies Figure 11: Distribution of Phi Coefficients for 11 Paired Responses, by Site, in 22 Sites Returning 1O Tests —1.0 —0.5 0.0 0.5 1.0 SITE _________F> 6 + 81 -( 95 —f1—-— — 103 — 104 125 + 165 179 189 (i]— 225 0 _____ 258 284 * 285 -1.0 -0.5 0.0 0.5 363 Page 64 Effectiveness of Infection Control Strategies Figure 11 (contj: —1.0 —0.5 0.0 0.5 1.0 SITE — 408 418 420 (.j .f )___ 452 - 481 ( 527 _______.j3EJE) 541 __ * 558 —1.0 —0.5 0.0 0.5 1.0 at variable distances apart from each other on the test and the influence of the order in which questions were presented was not studied experimentally. However, gross evidence of learning bias was not evident in a comparison of differences in scores on a first versus second question of each pair (Figure 4). Relationship Between Infection Control Knowledge and Practice In examining the relationship between knowledge and practice, this work failed to find a strong positive correlation. Since null hypothesis #4 was not rejected, one must consider the possibilities of insufficient statistical power to detect a true relationship, and of distortion by other variables (confounding). Page 65 Effectiveness of Infection Control Strategies Sixty observations provide z99% power to detect change in a hospital from random (50%) to minimally acceptable (at least 75%) compliance with gloving policy; a sample of 35 hospitals provides z93% power to detect strong positive correlations (r0.5). Thus, sample sizes appear to have been sufficient. However, knowledge and practice scores of individual nurses could not be linked because of logistical constraints and requirements of anonymity. Comparison of mean knowledge and practice scores for each hospital was a feasible but less refined approach. Pearson’s correlation coefficient provides greater statistical power to find statistically significant linear associations between normally— distributed variables than the Spearman coefficient; however, the latter is more robust to non—normal distribution and more powerful at finding nonlinear associations. The former was used on data that were normally distributed (or transformed into a normal distribution), and the latter when normality could not be assured. Since both coefficients were of similar magnitude and thus led to the same conclusions with these data, these conclusions are more likely to reflect true facts than to be artifacts of a particular statistical model. Univariate correlations between knowledge and practice scores approached a moderately strong positive level (Table 16), but this appears to have resulted from confounding (Figure 7). When analyses corrected for differing numbers and compositions of observations from the various hospitals, progressive improvement in quality of the data was associated with a negative trend in the correlation. Correlations found between knowledge and practice were not significant when each component of knowledge and practice scores was given equal weight (Table 16). Canonical correlation analysis suggested that stronger correlations might be achievable by contrasting various aspects of knowledge and practice rather than giving each aspect equal weight (Table 17). Failure to achieve statistical Page 66 Effectiveness of Infection Control Strategies significance in these multivariate models may be due to a small sample size (35 hospitals relative to 8 variables), since an accepted rule of thumb for multivariate analyses calls for at least ten observations per variable.79 However, more importantly, the models suggested are not readily interpretable by any logic concerning what is known about the importance of these component aspects of knowledge and practice. Bias in Knowledge, Practice and Injury Measurements The 35 hospitals providing covert observations, knowledge tests and needlestick rate data comprised a highly—motivated, non—random, self—selected sample. They were primarily large community—hospitals from urban centers all across Canada, but are not representative of all hospitals in size or type. Approximately 3% of western, mid—western and central but 10% of eastern hospitals participated. Smaller facilities tended to be excluded by the requirement to make observations in a critical care unit, and very few university—affiliated hospitals elected to participate. Further, nurses tested within these hospitals were also volunteers. As a consequence of volunteer bias,8° these results might therefore be considered to represent maximal rather than mean values if extrapolated to all hospitals. Given the anonymous nature of the covert observations and nurses’ tests, it was not possible to make any objective assessment as to the direction or degree of bias. Self—selection bias must therefore be considered an important limit to external validity. Selective reporting bias (e.g.: not reporting injuries from “clean” needles) and recall bias must also be kept in mind with regard to the needlestick injury data.8° Have Universal Precautions or Body Substance Isolation Been Effective as Harmonizing Strategies for Hospital Infection Control? Historically, numerous anecdotal reports and studies show poor compliance Page 67 Effectiveness of Infection Control Strategies as a common problem under traditional isolation approaches. Indeed, UP/BSI could be considered behavior modification strategies to achieve better compliance. However, most of the few studies documenting performance under these new strategies find poor compliance with infection control precautions under UP. Clements et al., in a covert “before and after” study, found higher rates of colonization and lower compliance with appropriate glove or gown use after implementing UP.8’ Conversely, Klein et al., in a randomized prospective study, found fewer infections and longer infection—free durations among pediatric ICU patients under a protocol similar to BSI as compared to standard care.82 Baroff et al.’s covert observation of a small number of emergency department procedures and subsequent staff interviews report results consistent with less than 50% compliance, poor exposure—risk knowledge, disagreement with gloving as providing protection during phlebotomy, and complaint that required protective eyewear was not readily available.83 This is consistent with Kelen et al.’s findings.84 Hammond et al. similarly found poor compliance during trauma care even if patients were already identified or suspected of HIV.85 Kaczmarek et al. found average glove—use rates of 92% (drawing arterial blood gas) to 71% (phlebotomy) with significant differences between states with high versus low AIDS incidence rates. They conclude that “glove utilization by health—care workers during procedures in which they may contact patient body fluids is substantial, but not universal.”06 Lynch et al. described improvement in knowledge and compliance on some but not all wards after an intense and comprehensive inservice effort.87 Wong et al. reported increased use of barrier garments (from 54% to 73%) associated with a decrease in exposure incidents following adoption of UP.88 However, unlike this thesis research which found composition of observations to be an important confounding variable, these Page 68 Effectiveness of Infection Control Strategies studies relied upon convenience samples rather than standardized covert observations. Further, completion of daily self—report forms in studies, such as that of Wong et al., may itself prompt behaviour changes artificially. Other self—report surveys that rely upon memory of past events are subject to well— recognized biases. Single—center studies might be considered as hypothesis— generating whereas multicenter research with standardized covert observations provides stronger evidence for or against universal trends. Hospitals have been motivated to adopt either UP or BSI to quell staff fears of occupationally—acquired HIV infection. Protection of staff against HIV has been the prime motivation for change in Canadian hospitals. This was evident in the administrative survey from reasons stated for adopting UP or BSI. It was also reflected in the finding that receipt of a staff education guideline published in HIV—related literature was more common in every size group than receipt of the BSI handwashing guideline that would not be found in HIV—related literature searches. This research confirms that, in practice, UP and BSI now mean different things in different hospitals. At the extremes, one site claiming to have implemented UP had eliminated specimen warning labels and all isolation categories other than ‘Respiratory”: this is essentially BSI. Two others claimed adoption of BSI, one specifically recommending against UP, yet retained all of the original isolation categories: this is essentially UP. In many hospitals claiming UP, glove use policy was more in line with BSI. A recommendation to limit UP primarily to visibly—bloody fluids was rejected by approximately half of the hospitals in each size group claiming both adoption of UP and receipt of this guideline. Further, additional terms were introduced by some respondents (“Routine Infection Control Precautions”, “Hygienic Precautions”, “General Page 69 - Effectiveness of Infection Control Strategies Precautions’, “Basic Precautions”, “Routine Precautions”, “Body Substance Precautions”, “Universal Barrier Precautions”, “Infection Control Precautions”). Some were synonyms for UP with precautions for all rather than just bloody body fluids; others were synonyms for BSI with more emphasis on handwashing. Several survey responses suggested confusion between the recently— proposed BSI protocol and CDC’s existing “Blood/Body Fluids Precautions” isolation category. This may be due to inadequate receipt of information: two reports by BSIs originators have not been received by a high proportion of Canadian ICP’s. Among respondents in the larger size groups claiming adoption of BSI, 36—60% and 18—40% reported not receiving the ANNALS OF INTERNAL MEDICINE and ASEPSIS issues cited. This confusion was also evident among nurses’ test responses: uniformly low scores were achieved on paired questions regarding fundamental differences between UP and BSI, and a number of nurses added written comments about being unfamiliar with the term BSI. A main finding of the administrative survey is that number of beds was the most significant determinant of guideline receipt. Fully one—third of hospitals under 200 beds had not received either CDWR or MMWR guidelines. This is in contrast to the reported American rates of 80% receiving and 50% reviewing CDC Isolation guidelines.’3 All size groups received federal guidelines more commonly than those published in topical review or medical journals. Although CDWR and the LCDC Guidelines series were distributed without charge to Canadian hospitals, neither was sent unless specifically requested. The original CDC Guidelines series issued in 1981 was mailed, unsolicited, to all U.S. acute—care hospitals. Presence of an ICP and of medical teaching programs were found to be additional significant determinants for receipt independent of bedsize, but interpretation of interaction terms (JCPsize and teachingsize) as Page 70 Effectiveness of Infection Control Strategies significant determinants of guideline receipt will require further study. Conflicting guideline statements regarding staphylococcal pneumonia provided an opportunity to consider the depth of review applied by hospitals. A CDC Guideline4 specifies a private room (as well as staff use of masks and gowns) for staphylococcal pneumonia or draining lung abscess. This is intended to control the extent of environmental contamination by virulent bacteria known for their ability to survive drying. An LCDC Guideline,89 derived from the CDC document, recommends neither private room nor masks, and specifies gowns for pneumonia but not lung abscess. Only two of the responding sites specifically commented on this discrepancy between CDC and LCDC documents, one stating that they had not previously noted it. The majority of Canadian hospitals adopting UP, BSI, or “Body Substance Precautions” have not eliminated special warning labels for recognized “infectious” cases, especially with regard to laboratory specimens. This may invite a double—standard. It is difficult to find evidence supporting a belief that such warning labels are effective prompts to take due caution.90 Over half of ward staff in one confidential survey admitted to routinely using inadequate infection control precautions in the care of patients known or suspected to have HIV infection.91 Limited accuracy of such labeling was documented by Handsfield et al., who found that only 67% of HIV and 28% of HB5Ag seropositive specimens were labelled.92 However, respondents commented that eliminating specimen warning labels is a controversial proposal. Similarly, Miller and Farr have reported that while 86% of hospital epidemologists agreed with UP and 69% of 121 US hospitals established UP as policy, 74% retained special signs to mark rooms of patients with HIV or hepatitis B.93 Only two collaborative efforts between neighboring hospitals were evident Page 71 Effectiveness of Infection Control Strategies in the administrative survey. Development of common guidelines and educational packages by an Ontario city’s Task Force for Implementation of Body Substance Precautions (BSP) (essentially BSI with greater emphasis on handwashing) was the most extensive. One Alberta hospital had initiated comprehensive studies and acted as a regional resource; while adopting “Universal Precautions”, their program retains only Respiratory Isolation, eliminates specimen warning labels, and rejects the limitation of UP to bloody fluids (thus, comparable to Ontario’s BSP). This lack of consistency between hospitals was reflected in observed staff practices. Failure to wear gloves at appropriate times has been associated with transmission of viral hepatitis and HIV.32 39 40 41 Addition of single— or double—gloving usually, but not invariably,93 has been associated with resolution in anecdotal hepatitis outbreak reports. While routine use of gloves as a universal precaution is a reasonable extension of logic, it remains to be demonstrated that the strategy is effective when scaled up. Whether such demonstration would improve staff compliance also remains to be shown, especially since a strong correlation between knowledge and practice was not found in this and another96 study. The optimal type and number of gloves to wear have also been points of controversy. Case reports and, more significantly, outbreak investigations using case—control and molecular—typing methods have implicated failure to wear any gloves during direct contact with blood or other body substances in the transmission of various nosocomial pathogens. While the potential severity of such infections is self—evident from these reports, the exact magnitude of this infection risk and of its reduction through routine use of gloves are not known. Handwashing, “no—touch technique” and selective use of gloves were considered Page 72 Effectiveness of Infection Control Strategies adequate in guidelines prior to the AIDS epidemic. However, in responding to fears triggered by AIDS, UP changed the focus of infection control from protecting patients to protecting healthcare workers. An historic emphasis on handwashing and no—touch technique changed to an emphasis on routine use of gloves. Blood contact with skin can be prevented by gloving.97 Double—gloving has been shown to reduce the extent of blood exposure during surgery;98 single— or double—gloving may be equally effective in reducing the volume of blood transferred from a needlestick by 5O%. BSI also stressed routine use of gloves, but for a different reason: handwashing and no—touch technique alone were not proving effective in resolving bacterial cross—infection problems. These new mandates to expand the use of gloves were based solely on extensions of logic. Logically, the next step would be to confirm assumptions of effectiveness. Unfortunately, attention quickly turned from epidemiologic study of glove effectiveness to laboratory study of glove function. “Leakage rates were reported in several papers during Session 55 (Protecting Health Care Personnel) at the October 1988 Interscience Conference on Antimicrobial Agents and Chemotherapy. While discussion stressed the epidemiologic fact that no excess risk has been demonstrable given a seemingly adequate though less—than—perfect barrier, Dr. Frank Young, Commissioner of Food & Drugs, reported to the Third National Forum on AIDS and Hepatitis B last November [19881 that leakage levels are ‘alarmingly high’ and that FDA plans to use ‘a more stringent and sensitive test for gloves than that used for screening condoms.”10° It remains to be demonstrated whether routine use of single— or double—gloves can reduce infection risk and whether any such effect is jeopardized by “alarmingly high” leakage rates. Further evidence against the effectiveness of new infection control Page 73 Effectiveness of Infection Control Strategies strategies adopted by Canadian acute—care hospitals was found in needlestick injury rates. In order to compare results of studies with varying durations of exposure time, annual risk of one or more needlestick injuries can be estimated as (1_(1_r)tj where ‘r’ equals a measured risk during shorter time intervals and “t” equals the number of such intervals in one year. The monthly risk of 2.3— 3.5% found in this research equates to an annual risk of z245—350 injuries per 1000 critical care nurses. The former figure is similar to an annual 273.4 injuries per 1000 registered nurses reported recently by McCormick et al.’°1 and higher than the 153—194 per 1000 nurses in a five—year study by Linnemann et al.102 The latter figure is similar to a recent survey of midwives in which 24% claimed one or more needlestick injuries in a preceding six—month period (422 per 1000 nurses annually).’03 Hamory, correcting for 40% under reporting, found an annual incidence rate of 611 per 1000 nurses and cautioned against reliance upon employee health records to assess changes in injury rates.’°4 Correction for under—reporting in the 2.3% health record based rate found in this research suggests a figure similar to that reported by Hamory. The level of risk found among Canadian critical care nurses is commensurate with previous reports and remains cause for concern. Beyond a potential for transmission of hepatitis B and HIV, the direct costs of sharps injury postexposure investigation and treatment are appreciable.’° 106 The perception that needle—handling practices have not improved, the confirmation that discarded needles are still recapped frequently, a finding of injury rates commensurate with rates reported prior to adoption of UP and BSI guidelines, demonstration of only borderline statistical significance in rate reduction trends and no evidence of a relationship between rates of needle recapping and needlestick injury in this multicenter hospital study reinforce a Page 74 Effectiveness of Infection Control Strategies suggestion that UP and BSI have missed the point on needlesticks.62 Needlestick injury is the predominant occupational exposure to HIV, and preventing occupational HIV exposure was expressed as Canadian hospitals’ primary motivation for adopting new infection control strategies. In conclusion, returning to Table l’s list of assessment criteria, these results provide little reason to believe that infection control practices have become uniform between or even within facilities under UP or BSI (Table 20). Guidelines defining these strategies were not received by all hospitals, especially those smaller facilities most in need of expert guidance, and the degree to which those receiving guidelines reviewed their content may not be adequate. There were inconsistencies in policies between nearby hospitals as well as within hospitals (e.g.: the low correlation between warning label use for housekeeping versus the laboratory). Appreciable proportions of nurses had not received inservice education and held divergent views. Appreciable proportions of nurses were observed to disregard their hospital’s policies on glove use and needle recapping in spite of expressed agreement with those policies. This research also failed to produce convincing evidence linking reduced needle recapping with reduced needlestick injury rates. The low level of effectiveness discovered for strategies which may cost as much as $10—million per case of HIV seroconversion prevented is disappointing. Recommendations for Improving the Research Tools Survey forms and questionnaires were designed, pretested and validated because established tools were not available. These new tools may be of value in future research studies and hospital quality assurance projects. The forms developed for the administrative survey could be useful for similar cross—sectional surveys in other countries, or for repeated surveys to Page 75 Effectiveness of Infection Control Strategies Table 20: Status of UP/BSI in Canadian Acute—Care Hospitals, 1990 EVALUATION FINDINGS WITH REGARD TO: CRITERION STRUCTURE PROCESS OUTPUT OUTCOME 1. Hospitals have z37% of <1% of all Few knew 19% could received adequate smaller hospitals how UP identify their information to hospitals noted major and BSI UP/BSI—related make informed didn’t conflict in differ costs decisions; receive CDC vs LCDC guidelines guidelines Hospitals adopted z75% claim appropriate policies UP or BSI; consistent with the 5% adopted system selected. all policies expected 2. Hospital staff Most sites Many nurses Mean staff Many nurses understand and mandated did not score z54% held divergent accept UP or BSI education receive on test of opinions and for all education knowledge disagreed with staff re: UP/BSI new policies 3. Staff adhere to All sites Hospitals Glove—use recommended UP or providing rarely compliance z6O% BSI guidelines in policies monitored but ranged widely their daily work mandated compliance among hospitals practices; protective or provided apparel. feed—back z50% of hospitals to staff reported 25% needle recapping Use of UP or BSI practices leads to Needlestick reduced infection injury rates risk, comparable before and after UP/BSI Page 76 Effectiveness of Infection Control Strategies study changes over time. This 1989 survey provided a picture of hospital operation at one point in time. It would be interesting to learn, for example, if guideline receipt patterns change or if more becomes known about costs and benefits of evolving new infection control strategies in the future. Two changes might make the questionnaires even more useful. First, since the types of “isolation’ used (e.g.: “Strict”, “Respiratory’, etc.) are intrinsic to defining which strategy or system was adopted by each hospital, this area should be made more explicit. Sufficient information was volunteered in open— text replies, but more explicit interrogation on this point would be prudent. Second, since the marginal costs of UP and BSI are poorly detailed and their benefits are even more obscure, a series of questions dealing with economic aspects should be added. A careful cost—effectiveness study of alternative infection control strategies would provide important information. The forms used to record covert observations of daily practice could be useful in hospitals’ on—going quality assurance audits. Substantial agreement among different ICPs’ independent observations of nursing practices was not confirmed in this research, but has been reported in a small study by others.107 Observer accuracy and agreement, essential to validity and reliability of infection control research studies, deserve further study. The composition of observations sampled was not evaluated as a potential confounding variable in previous studies, but was found as an important source of distortion in this research. Future studies should establish observation quotas and schedules, as was done in this research, rather than rely on convenience samples. It was not feasible to evaluate observers’ performance, for example in watching a videotape of specific nursing practices, but this could be considered in future studies. The knowledge and beliefs test validated in this study should be useful for Page 77 Effectiveness of Infection Control Strategies hospitals’ educational needs assessments and evaluation of in—service education programs. With minor modification, it would provide a practical, valid and sufficiently reliable means to measure knowledge of infection risks and control measures in nursing practice under UP/BSI. Such assessment is important in developing and promoting effective infection control programs. Use of this test in additional hospital studies is encouraged. This study used photocopied, double—sided forms with sequentially— numbered questions. Individual—history questions #7 and #32 (unscored items) and, collectively, questions #9—21 (the entire second page) were leftblank with disproportionate frequency. While only zl.6% of returned tests were spoiled by missing answers, this might be improved by better typeset quality or use of single—sided forms. Interactive response to a computerized “interview”, unlike use of forms, would allow direct control of quality (no missing answers, out—of—range responses, transcription errors, etc.) and encryption of data (supporting confidentiality for participating staff). The software provided required neither computing nor typing expertise to install or operate. However, results are in agreement with unpublished data suggesting that fewer than one—third of North American ICPs have computer support and nurses’ access to other computers is limited (market survey, Applied Epidemiology, Sidney, British Columbia). Computer—based survey of hospitals, whether by modem or mailed disks, is not yet a viable option for hospital epidemiology research. No serious ambiguity or validity concerns were expressed by ICPs aft)er receiving tabulated summaries of test results. Inclusion of test statements better answered by “yes” or “no” rather than on a Likert scale was identified as a source of difficulty in specific comments written on tests by critical care Page 78 Effectiveness of Infection Control Strategies nurses. Answers to such questions were penned in the margin rather than indicated on the Likert scale of several tests. Several test items regarding local policy were phrased as requiring or prohibiting certain practices; in retrospect, it would be preferable to substitute ‘encouraging’ or “discouraging” since alternatives were allowed in some policies (e.g.: discouraging needle recapping but offering a preferred method if recapping were deemed necessary). Potentially ambiguous test items specific to knowledge of local policy were therefore not scored. There is no “gold standard’ against which to establish criterion validity for this test. Satisfactory review by 35 ICPs is therefore important confirmation of test validity achieved through appropriate test content and expert consensus, but the test could be improved by rewording its local policy questions and substituting “yes/no” boxes for personal history responses. Further refinement and assessment of test reliability would also be desirable. The database management software written for this research is as important as the forms themselves. Without it, the task of accurately extracting data from the forms would be insurmountable. Designing, programming, debugging and documenting the code required a formidable number of hours. The existing database management system could be refined by adding user—level help or documentation; additional index files and options to search for hospitals by name, region, size, etc., rather than solely by site number; and by creating more standard output report formats now that the methods of analysis are defined. Speed of operation and size of files could also be improved by upgrading to a product release more recent than the version of F0xBASE used. Page 79 Effectiveness of Infection Control Strategies VI. Conclusions and Recommendations Health policy is influenced by political, cultural, economic and technological factors as well as by epidemiologic information. The latter is not always compelling and sometimes frankly ignored. Some hospital epidemiologists and infection control practitioners also have lacked sufficient status, authority, autonomy or support to shape hospital infection control policies efficiently.108 Hospitals adopt procedures believed effective to prevent infection and periodically modify their strategies when epidemiologic evaluations fail to document effectiveness. Universal Precautions and Body Substance Isolation are the most recent modifications, and these new national strategies were evaluated in this multi—center research. Table 20 indicates failures at all levels of structure, process, output and short—term outcome. The long—term outcome of reduced risk to hospital patients and health—care workers remains a noble goal. In order to achieve this, improvements are needed in the forces acting upon hospital practice (structure), the measures taken within hospitals themselves (process) and measurement of what actually is done as daily practice (output). A conceptual model of goals, objectives and related assumptions fundamental to all hospital infection control programs is shown in Appendix 1. Within this context, the following conclusions and recommendations are made. Beyond these, the relatively small number of hospitals completing all phases of this research underscores workload conflicts as a limiting factor. ICP staffing, supervision, computer support and priorities are related issues that cannot be addressed directly here. Alternatives to a traditional infection control program structure should be considered so that applied research may be supported more extensively in hospital epidemiology.109 Page 80 Effectiveness of Infection Control Strategies Recommendations for Improving New Infection Control Strategies 1. UP and BSI cannot be cost—effective solely in terms of protecting health care workers from blood—borne infection, the motivation for their adoption claimed most frequently in this research. UP and BSI are costly, their focus is on gloves and gowns whereas 70—90% of health care workers’ hepatitis B and HIV nosocomial infections derive from sharps injuries and the incidenceof such infections is already low. We need to refocus infection control on protecting patients as well as staff and visitors. BSI may be cost—effective in this broader context, but research to explore this must receive greater priority. 2. Sharps injuries pose a much greater risk of blood—borne infection for health care workers than does skin contact. However, this research found a relatively low proportion of hospitals using promising new protective devices in comparison to the larger proportion accepting increased costs for gloves and gowns. As noted by McCormick et al.,10 there should be commensurate spending to purchase and evaluate novel devices which could reduce sharps injuries. 3. UP and BSI are influential new initiatives, but have lost any specific meaning in practice. Three—quarters of Canadian hospitals adopted the names, but not all of the policies recommended in published guidelines for these strategies. Confusion over the meaning of UP and BSI was evident in survey responses. Fewer than half of the nurses in half of the hospitals surveyed felt that their hospital’s policies were practical, effective and well—documented. ICPs, hospital epidemiologists and other staff members in their hospitals should discuss the implications of these different strategies at the working level. UP and BSI need to be redefined from the perspective of health care workers, not consultants who are distant from provision of care itself. 4. Expert interpretation of research studies and consensus on recommended Page 81 Effectiveness of Infection Control Strategies practices is potentially beneficial to all hospitals and health—care agencies. Those with their own resources can use these guidelines as starting points. Those without in—house or networked expertise could accept such guidelines as a basis for responsible policies, but were found to be the least likely to have received published guidelines. This presents two problems: How many different expert working groups need to produce guidelines independently; how can current guidelines best be provided to hospitals? Better coordination should be a priority to reduce duplication of effort as well as opportunities to introduce contradictions and typographical errors which may mislead unwary end users. A plethora of guidelines and revisions for UP has been issued over the past few years from federal, state, provincial, regulatory and professional associations with but limited opportunity for widespread review of preliminary drafts by interested parties. Since these guideline updates and revisions are published at irregular intervals, are advertised in publications to which only some hospitals subscribe, and are not received unless specifically requested, a means for placing standing orders or otherwise improving distribution would help to assure that appropriate parties always have current versions of recommended practices. 5. Administrators need to ensure that a comprehensive, practical system emerges which is consistent with a guiding philosophy and capable of achieving clearly stated, realistic goals. Further, administrators need to ensure that policies in all departments throughout their hospital become consistent with the system selected as quickly as possible. Piecemeal implementation, poor knowledge of costs and inconsistency in policies were evident in this research. 6. The prospect of regulatory or accreditation agencies stifling applied research by mandating one set of unproven guidelines as the only acceptable Page 82 Effectiveness of Infection Control Strategies approach is cause for concern. The prospect of guidelines being accepted without careful review by qualified individuals in health—care institutions is equally distressing. This research failed to produce convincing evidence linking UP, BSI and avoidance of needle recapping with widespread improvement in rates of needlestick injury, the only quantifiable risk for occupational HIV transmission. As Gerberding recommends, “Until additional research clarifies the value of current infection control policies, standards should maximize institutional autonomy to develop rational strategies consistent with local practice and perceived needs.”9° Hospitals need tools now, not rules. 7. Higher priorities should be placed on having ICPs and hospital epidemiologists carefully assess implications of changes proposed in new guidelines, discuss new recommendations with other health—care workers so as to provide liaison with those who must actually live with proposed measures, and assist in establishing institutional process review audit mechanisms. Few hospitals were prepared to undertake such audits. This research documented widespread deficiencies in knowledge and policy compliance as well as lack of correlation between knowledge and practice. Validated audit tools are needed. 8. Noncompliance again was found to be a primary impediment to the effectiveness of infection control strategies. Innovative approaches to motivate behavior change must be developed and evaluated. Further research should seek unique features that distinguish between hospitals exhibiting relatively low versus high levels of staff compliance with policies. 9. In future studies, compliance should be measured by standardized covert observations. The number and composition of such observations was found to be an important confounding variable in this research. BSI was formulated through a fresh look at unresolved cross—infection Page 83 Effectiveness of Infection Control Strategies problems. UP replied to an emotional response triggered by the fatal nature of AIDS, not by quantified occupational—risk assessment of blood—borne diseases (hepatitis B, with its quantitatively higher risk of morbidity and mortality for health care workers, should have motivated the development of such precautions much earlier). This dichotomy, together with a paucity of hospital—initiated applied research found in the biomedical literature, prompts one final recommendation. Hospitals have traditionally focused on problem identification as their basis for quality assurance. Some hospitals are now expressing interest in industrial methods of Total Quality Management (TQM) and Continuous Quality Improvement (CQI).11° Infection control, like quality assurance, should be viewed as a journey of evolution, not simply enforced compliance with one set of rules. Administrators are long overdue in expecting qualified infection control or hospital epidemiology staff to provide important program planning and evaluation information.11’112 In fact, TQM and CQI bear many similarities to Williamson’s method for finding “achievable benefit not achieved” opportunities to improve quality of service.”3 Hospital epidemiology and infection control programs should be expected and supported to provide the tools and mechanisms to take fresh looks at all aspects of hospital service. Their heritage of being reactive to adverse events will not continue to suffice in a future that requires a proactive focus on quality improvement. Page 84 E’ffectiveness of Infection Control Strategies Bibliography 1. LaForce FM. The Control of Infections in Hospitals: 1750 to 1950. In: Wenzel RP, ed. PREVENTION AND CONTROL OF NOSOCOMIAL INFECTIONS. Baltimore. MD: Williams and Wilkins 1987:1—12. 2. Bullock WE. Control of Nosocomial Infections Through Patient Isolation. In: PROCEEDINGS OF THE NATIONAL CONFERENCE ON INSTITUTIONALLY ACQUIRED INFECTIONS. Washington DC: U.S. Government Printing Office 1964:153—161 3. Eickhoff TC. International Symposium on Control of Nosocomial Infections: Synthesis and Summary. In: Sacks T, McGowan JE Jr, eds. International Symposium on Control of Nosocomial Infection. REV INFECT DIS 1981;3(4): 798—803. 4. Garner JS, Simmons BP. Centers for Disease Control Guideline for Isolation Precautions in Hospitals. INFECT CONTROL. 1983;4(4):245—325. 5. Nauseef WM, Maki DG. A Study of the Value of Simple Protective Isolation in Patients with Granulocytopenia. N ENGL J MED 1981;304(8):448—453. 6. Pettinger A, Nettleman MD. Epidemiology of Isolation Precautions. INFECT CONTROL HOSP EPIDEMIOL 1991; 12(5):303—307. 7. Centers for Disease Control. Recommendations for prevention of HIV transmission in health—care settings. MMWR 1987;36(suppl 2):3S—18S. 8. Jackson MM, Lynch P. Cummings MJ, Stamm WE. Rethinking the Role of Isolation Practices in the Prevention of Nosocomial Infections. ANN INTERN MED 1987;107:243—246. 9. Garner JS, Hughes JM. Options for Isolation Precautions. ANN INTERN MED 1987; 107:248—250. 10. Campbell B. An Open Letter to Infection Control Personnel. DIMENSIONS IN HEALTH SERVICE 1988;Feb.:40. 11. CDC. Update: Universal Precautions for Prevention of Transmission of Human Immunodeficiency Virus, Hepatitis B Virus and Other Bloodborne Pathogens in Healthcare Settings. MMWR 1988;37(24):377—88. 12. Manian F. Universal Precautions TClarified”? INFECT CONTROL HOSP EPIDEMIOL l988;9(8):343—4. 13. Celentano DD, Morlock LL. Malitz FE. Diffusion and Adoption of CDC Guidelines for the Prevention and Control of Nosocomial Infections in US Hospitals. INFECT CONTROL 1987;8(lO):415—423. 14. Gerberding JL, Henderson DK. Design of Rational Infection Control Policies for Human Immunodeficiency Virus Infection. J INFECT DIS 1987;156(6):861— 864. Page 85 Effectiveness of Infection Control Strategies 15. Department of Labor, Department of Health and Human Services. Joint Advisory Notice: Protection Against Occupational Exposure to Hepatitis B Virus (HBV) and Human Immunodeficiency Virus (HIV). FEDERAL REGISTER l987;52(210)41818—41823. 16. Birnbaum D, Kelly M, Chow AW. Epidemiologic Typing Systems for Coagulase— Negative Staphylococci. INFECT CONTROL HOSP EPIDEMIOL 1991;12(5):319—26. 17. Suchman EA. EVALUATIVE RESEARCH. New York, NY: Russel Sage Foundation; 1967:115. 18. Woodward CA, Chambers LW, Smith KD. GUIDE TO IMPROVED DATA COLLECTION IN HEALTH AND HEALTH-CARE SURVEYS. Canadian Public Health Association: 1982. 19. Knapp TR. Validity, Reliability, and Neither. NURSING RESEARCH 1985;34(3): 189—1 92. 20. Weinstein RA, Kabins SA. Isolation Practices in Hospitals. ANN INTERN MED 1 987;5(107):781 —782. 21. Doebbeling BN, Pfaller MA, Houston AK, et al. Removal of Nosocomial Pathogens from the Contaminated Glove, Implications for Glove Reuse and Handwashing. ANN INTERN MED 1988; 1 09:394—398. 22. Cochran WG. SAMPLING TECHNIQUES, 3rd edition. New York NY: John Wiley & Sons 1977:Equations #5A.42, 13.2 and 13.3. 23. Miettinen OS. THEORETICAL EPIDEMIOLOGY, PRINCIPLES OF OCCURRENCE RESEARCH IN MEDICINE. New York, NY: John Wiley & Sons 1985:pp.136—7. 24. Larson E. A Causal Link between Handwashing & Risk of Infection? Examination of the Evidence. INFECT CONTROL HOSP EPIDEMIOL 1988;9(1):29—36. 25. Fox MK, Langner SB, Wells RW. How Good are Handwashing Practices?. AM J NURSING 1974;74(9):1676—8. 26. Albert RK, Condie F. Handwashing Patterns in Medical Intensive—Care Units. N ENGL J MED 1981;304(24):1465—6. 27. Mayer JA, Dubbert PM, Miller M, et al. Increasing Handwashing in an Intensive Care Unit. INFECTION CONTROL 1986;7(5):259—62. 28. Kaplan LM, McGuckin M. Increasing Handwashing Compliance with More Accessible Sinks. INFECTION CONTROL 1 986;7(8):408— 10. 29. De Carvalho M, Lopes 3M, Pellitteri M. Frequency & Duration of Handwashing in a Neonatal Intensive Care Unit. PEDIATR INFECT DIS 3 l989;8(3):179—80. 30. Simmons B, Bryant 3, Neiman K, et al. The Role of Handwashing in Prevention of Endemic Intensive Care Unit Infections. INFECT CONTROL HOSP EPIDEMIOL 1900;l1(l1):589—94. Page 86 Effectiveness of Infection Control Strategies 31. Adams G, Stover BH, Keenlyside RA, Hooton TM, Buchman TG, et al. Nosocomial Herpetic Infections in a pediatric intensive care unit. AM J EPIDEMIOL 1981;113(2):126—32. 32. Baptiste R, Koziol D, Henderson DK. Nosocomial Transmission of Hepatitis A in an Adult Population. INFECTION CONTROL 1987;8(9):364—70. 33. Casewell M, Phillips I. Hands as Route of Transmission for Kiebsiella species. BMJ 1977;l9Nov:1315—7. 34. CDC. Nosocomial Acquisition of Aeromonas hydrophila. National Nosocomial Infections Study Report, Annual Summary 1977, Issued November 1979; pp23—5. 35. CDC. Acinetobacter calcoaceticus: Common Nosocomial Organism, Uncommon Pathogen. National Nosocomial Infections Study Report, Annual Summary 1976, Issued 1978, ppll—13. 36. Church DL, Bryant HE. Investigation of Streptococcus viridans Pseudobacteremia Epidemic at a University Teaching Hospital. INFECT CONTROL HOSP EPIDEMIOL 1989;10(9):416—21. 37. McFarland LV, Mulligan ME, Kwok RYY, et al. Nosocomial Acquisition of Clostridium diffIcile Infection. N ENGL J MED 1989;320:204—210. 38. Johnson S, Gerding DN, Olson MM, et al. Prospective Controlled Study of Vinyl Glove Use to Interrupt Clostridium difficile Nosocomial Transmission. AM J MED 1990;88:l37—40. 39. Snydman DR, Hindman SH, Winelanci MD, et al. Nosocomial Viral Hepatitis B: A Cluster Among Staff with Subsequent Transmission to Patients. ANN INTERN MED 1976;85:573—7. 40. CDC. Apparent Transmission of Human T—Lymphotropic Virus Type 111/ Lymphadenopathy—Associated Virus from a Child to a Mother Providing Health Care. MMWR 1986;35(5):76—9. 41. CDC. Update: human immunodeficiency virus infection in health—care workers exposed to blood of infected patients. MMWR 1987;36(19):285—9. 42. Beaumont LR. Detection of Blood on Nonporous Environmental Surfaces: An Approach for Assessing Factors Contributing to the Risk of Occupational Exposure to Blood in the Autopsy Suite. INFECTION CONTROL 1987 ;8( 10) : 424—9. 43. York MK. Bacillus Species Pseudobacteremia Traced to Contaminated Gloves Used in Collection of Blood from Patients with Acquired Immunodeficiency Syndrome. J CLIN MICROBIOL 1990;28(9):2114—16. 44. Patterson JE, Vecchio J, Pantelick EL, et al. Association of Contaminated Gloves with Transmission of Acinetobacter calcoaceticus var, anitratus in an Intensive Care Unit. AM J MED 1991;91:479—83. Page 87 Effectiveness of Infection Control Strategies 45. Bagg J, Jenkins S, Barker GR. Laboratory Assessment of the Antimicrobial Effectiveness of Glove Washing and Re—Use in Dental Practice. J HOSP INFECT 1990;15:73—82. 46. Korniewicz DM, Laughon BE, Cyr WH, et al. Leakage of Virus through Used Vinyl and Latex Examination Gloves. J CLIN MICROBIOL 1990;28(4):787—8. 47. Cookson B, Peters B, Webster M, et al. Staff Carriage of Epidemic Methicillin—Resistant Staphylococcus aureus. J CLIN MICROBIOL 1989;27(7):1471—6. 48. Doebbeling BN, Pfaller MA, Houston AK, Wenzel RP. Removal of Nosocomial Pathogens from the Contaminated Glove — Implications for Reuse. ANN INTERN MED 1988;109(5):394—8. 49. Larson E. Reported Cases of Allergic Reactions to latex Gloves on the Rise. INFECT CONTROL 110SF EPIDEMIOL 1991; 1 2(8):504—5. 50. Daschner FD, Habel H. HIV Prophylaxis with Punctured Gloves (letter). INFECT CONTROL HOSP EPIDEMIOL 1 988;9(5): 184—6. 51. Thomas GA, Talbot G, Jahre J, et al. Prospective Evaluation of Health—Care Workers Exposed via Parenteral or Mucous—Membrane Routes to Blood and Body Fluids of Patients with Acquired Immunodeficiency Syndrome. MMWR 1 984;33(13): 181—182. 52. CDC. Update: Prospective Evaluation of Health—Care Workers Exposed via the Parenteral or Mucous—Membrane Route to Blood or Body Fluids from Patients with Acquired Immuno—Deficiency Syndrome— United States. MMWR 1985;34(7): 101 —3. 53. Nadler J, Landesman 5, Rechtman D, et al. Update: Evaluation of HTLV— III/LAV Infection in Health-Care Personnel— United States. MMWR 1 985;34(38):575—8. 54. Stricof RL, Mores DL. HTLV—III/LAV Seroconversion Following A Deep Intramuscular Needlestick Injury. N ENGL J MED 1986;314(17):1115. 55. McCray E. Occupational Risk of the Acquired Immunodeficiency Syndrome Among Health—care Workers. N ENGL J MED 1986;314(7):1127—32. 56. Oksenhendler E, Harzic M, LeRoux JM. I-fly Infection with Seroconversion after a Superficial Needlestick Injury to the Finger. N ENGL J MED 1 986;315(9):582. 57. Neisson—Vernant C, Arfi 5, Methez D, et al. Needlestick HIV Seroconversion in a Nurse. LANCET 1986;ii;814. 58. CDC. Apparent Transmission of Human T—Lymphotropic Virus Type JIT/Lymphadenopathy—Associated Virus from a Child to a Mother Providing Health—care. MMWR 1986;35(5):76—79. Page 88 Effectiveness of Infection Control Strategies 59. Elmslie K. OShaughnessy MV. National Surveillance Program on Occupational Exposure to HIV Among Health—Care Workers in Canada. CDWR 1987; 13(37): 163—6. 60. Marcus R, CDC Cooperative Needlestick Surveillance Group. Surveillance of Health—care Workers Exposed to Blood from Patients with the Human Immunodeficiency Virus. N ENGL J MED 1988;319:1118—23. 61. Mangione CM, Gerberding JL, Cummings SR. Occupational Exposure to HIV: Frequency and Rates of Underreporting of Percutaneous and Mucocutaneous Exposures by Medical Housestaff. AM J MED 1991;90:85—90. 62. Jagger J. Pearson RD. Universal Precautions: Still Missing the Point on Needlesticks. INFECT CONTROL HOSP EPIDEMIOL 1991; 12(4):2 11—13. 63. Machin D, Campbell MJ. STATISTICAL TABLES FOR THE DESIGN OF CLINICAL TRIALS. Blackwell Scientific Publications, Oxford. 1987. Table 12.1. 64. McGill R, Tukey JW, Larsen WA. Variations of Box Plots. THE AMERICAN STATISTICIAN 1978;32:12—16. 65. Dallal GE, Wilkinson L. An Analytic Approximation to the Distribution of Lililefors’ Test Statistic for Normality. AMERICAN STATISTICIAN 1986;40(4):294—6. 66. Rothman KJ. MODERN EPIDEMIOLOGY. Boston, Mass.: Little, Brown & Company; 1986:41 —49. 67. Cleveland WS. THE ELEMENTS OF GRAPHING DATA. Monterey, CA: Wadsworth, Inc.; 1985:118—23. 68. Johnson RA, Wichern DW. APPLIED MULTIVARIATE STATISTICAL ANALYSIS. 2nd ed. Englewood Cliffs, New Jersey: Prentice Hall mc; 1988:438—69. 69. Geigy Scientific Tables. 7th ed. Switzerland: CIBA—GEIGY Ltd; 1970:66. 70. Fishman M. Cathers AP, Stamp D. Needle Punctures — Documentation and Incidence Rate Calculation. INFECTION CONTROL 1 985;6(1 ):35—36. 71. Remington RD, Schork MA. STATISTICS WITH APPLICATIONS TO THE BIOLOGICAL AND HEALTH SCIENCES. Englewood Cliffs, New Jersey. Prentice Hall Inc. 1985:316—319. 72. Doebbeling BN, Wenzel RP. The Direct Costs of Universal Precautions in a Teaching Hospital. JAMA 1990;264(16):2083—87. 73. Stock SR, Gafni A, Bloch RE’. Universal precautions to prevent HIV transmission to health care workers: an economic analysis. CAN MED ASSOC J 1990;142(9):937—46. 74. Abramson JH. MAKING SENSE OF DATA. New York, NY: Oxford University Press; 1988. Page 89 Effectiveness of Infection Control Strategies 75. Lilliefors HW. On the Kolmogorov—Smirnov Test for Normality with Mean and Variance Unknown. J AMERICAN STATISTICAL ASSOC 1967 ;62 :399—402. 76. Kuder GF, Richardson MW. The Theory of the Estimation of Test Reliability. PSYCHOMETRIKA 1937;2(3):151—60. 77. Lord FM, Novick MR. STATISTICAL THEORIES OF MENTAL TEST SCORES. Reading, Mass.: Addison—Wesley 1968:84, 336 (equations 4.2.10 and 15.5.9) 78. Hedges LV. STATISTICAL METHODOLOGY IN META-ANALYSIS. ERIC/TM Report 83, University of Chicago, 1982. pp.55—61. 79. Flury B, Riedwyl H. MULTIVARIATE STATISTICS, A PRACTICAL APPROACH. New York, NY: Chapman and Hall; 1988:9. 80. Sackett DL. Bias in Analytic Research. J CHRON DIS 1979;32:51—63. 81. Clements JS, Hampton KD, Wasilauskas BL, et al. Impact of Universal Precautions on the Acquisition of Gentamicin—Resistant Gram Negative Bacilli in a University Intensive Care Unit. abstract #787, 1989 Interscience Conference on Antimicrobial Agents and Chemotherapy. 82. Klein BS, Perloff WH, Maki DG. Reduction of Nosocomial Infection During Pediatric Intensive Care by Protective Isolation. N ENGL J MED 1989;320(26):1714—21. 83. Baraff U, Talan DA. Compliance with Universal Precautions in a University Hospital Emergency Department ANN EMERG MED 1989;18:654—7. 84. Kelen G, DiGiovanna T, Kalainov D, et al. Adherence to Universal Precautions by HCWs in an Inner—City Emergency Department with High HIV-1 Prevalence among Patients. abstract W.A.O.4, 5th International Conference on AIDS, June 1989, Montreal. 85. Hammond JS, Eckes JM, Gomez GA, Cunningham DN. HIV, Trauma and Infection Control: Universal Precautions Are Universally Ignored. J TRAUMA 1 990;30(5):555—61. 86. Kaczmarek RG, Moore RM Jr, McCrohan J, Lowe JT. Multi—state Investigation of Glove Utilization by Health—care Providers. Abstract Cli, 3’rd International Conference on Nosocomial Infections, Atlanta GA, 1990. 87. Lynch P, Cummings MJ, Roberts PL, et al. Implementing and evaluating a system of generic infection precautions: body substance isolation. AM J INFECT CONTROL 1990;18:1—12. 88. Wong ES, Stotka JL, Chinchilli VM, et al. Are Universal Precautions Effective in Reducing the Number of Occupational Exposures Among Health—care Workers? JAMA 1991;265(9):1123—28. 89. Bureau of Infection Control, Health & Welfare Canada. Infection Control Guidelines for Isolation and Precaution Techniques. 1985. Page 90 Effectiveness of Infection Control Strategies 90. Gerberding JL. Does Knowledge of Human Immunodeficiency Virus Infection Decrease the Frequency of Occupational Exposure to Blood? AM J MED 1991;91(suppl 3B):308S—311S. 91. Gerberding JL, Bryant—LeBlanc CE, Nelson K, et al. Risk of Transmitting the Human Immunodeficiency Virus, Cytomegalovirus & Hepatitis B Virus to Health Care Workers Exposed to Patients with AIDS & AIDS—Related Conditions. J INFECT DIS 1987;156(l):l—8. 92. Handsfield HH, Cummings MJ, Swenson PD. Prevalence of Antibody to Human Immunodeficiency Virus and Hepatitis B Surface Antigen in Blood Samples Submitted to a Hospital Laboratory— Implications for Handling Specimens. JAMA 1987;258(23):3395—7. 93. Miller P, Farr B. A survey of SHEA Members on Universal Precautions and HIV Screening. INFECT CONTROL HOSP EPIDEMIOL 1988;9(4):163—5. 94. Hamm RH, Peare RB, Painter WL, et al. Hepatitis B among Dental Patients— Indiana. MMWR 1985;34(5):73—5. 95. Lettau LA, Smith D, Williams D, et al. Transmission of Hepatitis B with resultant Restriction of Surgical Practice. JAMA 1986;255:934—7. 96. Gruber M, Beavers FE, Johnson B, et al. The Relationship between Knowledge about Acquired Immunodeficiency Syndrome and the Implementation of Universal Precautions by Registered Nurses. CLINICAL NURSE SPECIALIST 1 989;3(4): 182—5. 97. Bell DM. Human Immunodeficiency Virus Transmission in Health Care Settings: Risk and Risk Reduction. AM J MED 1991;91(suppl 3B):294S—300S. 98. Gerberding JL, Littell C, Tarkington A, et al. Risk of Exposure of Surgical Personnel during Surgery at San Francisco General Hospital. N ENGL J MED 1 990;322(25): 1788—93. 99. Mast ST, Gerberding JL. Factors Predicting Infectivity Following Needlestick Exposure to HIV in an in vitro Model. CLIN RES 1991;39(l):58A. 100. Birnbaum D. The informed use of technology. JOURNAL OF HEALTHCARE MATERIEL MANAGEMENT 1 989;7(4):86. 101. McCormick RD, Meisch M, Ircinik F, Maki DG. Epidemiology of Hospital Sharps Injuries: A 14—Year Perspective in the Pre—AIDS and AIDS Eras. Abstract #93, 3’rd Decennial International Conference on Nosocomial Infections. Centers for Disease Control, Atlanta, Georgia, 1990. 102. Linnemann Jr. CC, Cannon C, DeRonde M, Lamphear B. Effect of Educational Programs, Rigid Sharps Containers, and Universal Precautions on Reported Needlestick Injuries in Healthcare Workers. INFECT CONTROL HOSP EPIDEMIOL 1991;12(4):214—219. Page 91 Effectiveness of Infection Control Strategies 103. Loewen NL, Dhillon GL, Willy ME, Wesley RA, Henderson DK. Use of Precautions by Nurse—Midwives to Prevent Occupational Infections with HIV and Other Blood—Borne Diseases. J NURSE MIDWIFERY 1989;34(6):309— 317. 104. Hamory BH. Underreporting of needlestick injuries in a university hospital. AM J INFECT CONTROL 1983;11(5):174—177. 105. McCormick RD, Meisch MG, Ircink FG, Maki DG. Epidemiology of Hospital Sharps Injuries: A 14—Year Prospective Study in the Pre—AIDS and AIDS Eras. AM J MED 1991;91(suppl 3B):301S—307S. 106. Jagger J, Hunt EH, Pearson RD. Estimated Cost of Needlestick Injuries for Six Major Needled Devices. INFECT CONTROL HOSP EPIDEMIOL 1990; 11(1 1):584—88. 107. Gauthier DK, Turner JG, Langley LG, et al. Monitoring Universal Precautions: A New Assessment Tool. INFECT CONTROL HOSP EPIDEMIOL 199 1;12(10):597—601. 108. Soule BM. The Evolution of our Profession: Lessons from Darwin. AM J INFECT CONTROL 1991;19(1):45—59. 109. Birnbaum D. Infection control consortia. J HEALTHCARE MATERIEL MANAGEMENT 1991;9(9):76—77. 110. Murdock M. Continuous improvement in health—care: An overview. J HEALTHCARE MATERIEL MANAGEMENT 1991 ;9(1):72-3. 111. Massanari RM. Risk Management: An Epidemiological Approach (Editorial). INFECTION CONTROL 1987;8(1):3—6. 112. Wenzel RP, Pfaller MA. Infection Control: The Premier Quality Assessment Program in United States Hospitals. AM J MED 1991;91(suppl 3B):27S—31S. 113. Williamson JW. Formulating Priorities for Quality Assurance Activity. JAMA 1978;239(7):631—37. Page 92 Effectiveness of Infection Control Strategies Appendix 1: Conceptual Models: Comparison of Isolation Strategies Infection Control Goals, Objectives and Assumptions Page 93 Effectiveness of Infection Control Strategies Table 21: Comparison of Isolation Strategies STRATEGY: PURPOSE: PROMPTED BY: APPLIES ¶I): DESCRIPTION: TRADITIC*ThL STRATEGIFS: Category—Specific Prevent the Patient’s Certain body Selective Isolation spread of Diagnosis fluids and application of CDC, 1983 microorganisms substances supplementary among patients, (disease- precautions personnel and specific) grouped into visitors, categories Disease—Specific Prevent the Patient’s Certain body Selective Isolation spread of Diagnosis fluids and application of CDC, 1983 microorganisms substances supplementary among patients, (disease— precautions personnel and specific) selected item— visitors. by—item NEW STRATEGIES: Body Substance Reduce cross- Type of All body Replaces Isolation infection risk Patient fluids and Category— or Lynch, Jackson to patients, Contact substances Disease—Specific et al. 1987 and protect staff System with one frc*n microorganisms set of hygienic harbored by patients measures for all Universal Precautions Reduce risk to Type of AU body A basic level CDC, 1987 staff from Patient fluids and of hygienic bloodhorne Contact substances measures used in pathogens conjunction with traditional system Universal Precautions Reduce risk to Type of Body fluids A basic level CDC, 1988 Revision staff from Patient associated of hygienic bloodborne Contact with measures used in pathogens and Body hepatitis B conjunction with Fluid transmission traditional system Page 94 Effectiveness of Infection Control Strategies Table 22: Infection Control Goals, Objectives and Assumptions Long—term Goals: 1. Minimized occupational risk of nosocomial infection for staff 2. Minimized iatrogenic risk of nosocomial infection for patients 3. Minimized risk of widespread antimicrobial resistance for community Assumptions: 1. Staff and patients can be infected through exposure incidents, but these incidents are preventable through “isolation” and/or other precaution protocols. UP assumes that isolation of identified cases is necessary and effective; BSI assumes that all cases cannot be identified reliably and that special isolation” protocols to prevent direct or indirect contact transmission are inappropriate. 2. Hospital—acquired infections are sufficiently serious to warrant preventive action. 3. Transmission of exogenous infection to patients can be prevented. 4. Following expert guidelines will, in fact, reduce infection risk. 5. Prevention is more cost—effective than treatment alone. 6. Cross—infection contributes more to the prevalence of drug resistance than de novo development of resistant organisms. 7. Hospitals are major sources of novel drug resistance in the community. Intermediate—term Objectives 1. Institutions will develop and update infection control policies and procedures from pertinent published guidelines. 2. Staff will follow infection control policies and procedures in providing patient care. 3. Hospitals will monitor infection rates and staff performance. Assumptions: 1. Institutional programs review appropriate sources of information. 2. Policies developed from guidelines and refined through in—house monitoring are perceived as practical and beneficial by ward staff. 3. UP assumes that “isolation” is an effective behaviour—prompt to improve handwashing and gloving; BSI assumes that a multitude of isolation types is unnecessarily confusing. Short—term Objectives 1. Pertinent expert guidelines will be available to hospitals. Assumptions: 1. Guidelines will be effective in shaping institutional policy. 2. Expert interpretation is required. Page 95 Effectiveness of Infection Control Strategies Appendix 2: Hospital Survey Questionnaire Forms English Version French Version Page 96 Effectiveness of Infection Control Strategies TO: INFECTION CONTROL PRACTITIONER FROM: David Birnbaum, MPH RE: Evaluation of Universal Precautions/Body Substance Isolation INTRODUCTION: I am a Ph.D. student registered in an interdisciplinary program at University of British Columbia, supported by a Fellowship from the National Health Research and Development Program of Health and Welfare Canada. My thesis studies use and effectiveness of Universal Precautions and Body Substance Isolation. This study is endorsed by the Canadian Hospital Association. Your assistance in consenting to participate by completing this confidential questionnaire will be greatly appreciated. It should take no more than 15 minutes, and you are under no obligation to participate in subsequent phases. This first phase investigates current Canadian hospital practices; a second phase will involve on—site study of implementation in selected hospitals; the final phase will compare effectiveness in reducing infection exposure risks to patients or staff. This questionnaire provides the means to indicate if you would like to receive preliminary results or details of subsequent phases. Published results will not identify individual facilities nor infection control practitioners by name or location. Please return your completed questionnaire in the mailing envelope provided or by FAX (604—875—4013). Please include your mailing address if you wish to receive final results of this survey or wish to participate further. FACILITY DESCRIPTION: Please fill in the blank or circle the appropriate number(s) to describe your facility: 1. MAJOR FUNCTION: (1) Acute—Care Primary Community Hospital (2) Acute—Care Regional Referral Hospital (3) University Teaching Hospital (4) Residential Care Facility (5) Other (specify) ___________________________ 2. NUMBER OF BEDS: ______ 3. NUMBER OF INPATIENTS/YEAR: _____ 4. NUMBER OF OUTPATIENTS/YEAR: 5. NUMBER OF INFECTION CONTROL PRACTITIONERS: FULL-TIME — PART-TIME — 6. LOCATION: (1) City Centre (3) Town/Village (2) City Suburb (4) Unincorporated Area 7. DO YOU PROVIDE: (1) Hemodialysis (4) Internships (2) Drug Abuse Clinics (5) Residency Training (3) STD/AIDS Clinics 8. WHEN WERE YOU LAST ACCREDITED? Date _ _ _ Agency Status Page 97 Effectiveness of Infection Control Strategies UNIVERSAL PRECAUTIONS/BODY SUBSTANCE ISOLATION Has your facility made a formal decision to adopt or reject UNIVERSAL PRECAUTIONS or BODY SUBSTANCE ISOLATION? Which one? What factors were influential in the decision? What advantages and problems do you foresee in implementing these strategies? Do you have any data regarding implementation or operating costs as compared to category— or disease—specific isolation programs? Regardless of policy, do you feel that at least half of ward staffs still recap used needles? What type of disposal containers are in use, and how are needles transported from the point of use to the point of disposal (ie: recapped, placed on tray, stabbed into foam block, hand—carried, etc.)? What additional information would you want, if any, in order to confidently recommend for or against Universal Precautions? .to recommend for or against Body Substance Isolation? Page 98 Effectiveness of Infection Control Strategies CURRENT POLICIES: FOR ERCR POLICY PLEASR FILL I XITBXR OE YIS’ OR O BOX I 11CR COLUfl YO HiDICITX IF YOU Bill ALRRW: RECEIVED PUBLICATION REVThE) PUBLICATION ADOPTED GIJIDELThTE POLICY GUIDELINE & SOURCE: YES NO YES NO YES-DATE (nn/yj) NO Universal Precautions ends need for warning labels on specinens. CANADA DISEASES WEEKLY REPORT 1987;1353 Handwashing is unnecessary after removing gloves worn for anticipated contact with blood, secretions • mucous membranes or lesions unless hands are visibly soiled. ANN I1T1’ERN MED 1987;107:243 Private room is recommended for Staph. pneumonia. 1983 CDC “GUIDELINE FOR ISOLATION PRECAUTIONS IN HOSPITALS” Private room not reccnanended for Staph. pneumonia. 1985 HEALTH & WELFARE CANADA “ISOLATION AND PRECAUTION TECHNIQUES” INFECTION CONTROL GUIDELINES Securely bag all trash & linen to prevent leakage; no additional labels, double bags or special handling are needed for infectious cases. ASEPSIS 1986;8(4):2 Health care workers should be trained in infection— control procedures designed to prevent transmission of blood-borne pathogens and be advised to use these procedures for ail patients. N FGL NED 1986;315:1562 Universal Precautions don’t apply to feces, urine, nasal secretions, sputum, sweat, tears, voinitus, saliva or breast milk unless they contain visible blood. MMWR 1988;37(24):377 LI LI o o o o II LI LI 0 LI LI o o 11 LI LI LI LI LI LI LI LI LI LI LI LI LI LI _____ LI LI LI LI LI LI YES NO LI LI LI LI LI LI LI Would you like to receive preliminary results of this study? Would you like to participate further in this study? YES_ NO Page 99 Effectiveness of Infection Control Strategies AU: Directeur du programme de contrôle des infections DE: David Birnbaum, MPH RE: Iva1uation des Precautions élémentaires/Isolation des substances organiques INTRODUCTION: Je suis un étudiant au doctorat, inscrit a un programme interdisciplinaire a PUniversité de Colombie—britannique. Je suis également boursier du Programme national de recherche et de développement en matière de sante. Mon sujet de these est l’utilisation et l’efficacité des Precautions élémentaires et de l’Isolation des substances orgarLiques. Cette recherche est approuvée par lAssociation des hôpitaux du Canada. Votre participation sera fort appreciée; ii &agit de completer ce questionnaire confidentiel. Cela ne prendra que 15 minutes et vous nétes pas oblige de participer aux etapes subséquentes. Cette premiere étape est une étude des pratiques actuelles dans les höpitaux canadiens; une seconde etape consistera a limplantation dans des hôpitaux sélectionnés; Ia dernière étape comparera lefficacité a réduire les risques dinfection pour les patients et le personnel. Ce questionnaire vous permettra dindiquer si vous désirez recevoir les résultats préliminaires ou le detail des etapes subséquentes. Les résultats nidentifieront pas les individus et les institutions ayant participé, ni par leur nom, ni par leur emplacement. Veuillez sil—vous—plaIt retourner ce questionnaire rempli dans lenveloppe ci—incluse ou par FAX (604—875—4013). N’oubliez pas dajouter votre adresse Si VOUS désirez recevoir les résultats finals de cette enquête ou Si vous voulez participer aux etapes subséquentes. DESCRIPTION DE L’ITABLISSEMENT: Prdre do rdpondre dans lespace laissd en blanc on encore dencercier [e ou les nundros dbcrivant votre établissenent: 1. PRINCIPALE FONCTION: (1) hãpital communautaire de soins aigus (2) hôpital regional de références (3) hôpital denseignement universitaire (4) établissement résidentiel (5) Autre (spécifiez)__________________________ 2. NOMBRE DE LITS: _______ 3. NOMBRE DE PATIENTS PAR ANNE:_____ 4. NOMBRE DE CONSULTATIONS EN CLINIQUES EXTERNES PAR ANNE:______ 5. NOMBRE DE PRATICIENS AU CONTROLE DES INFECTIONS: a plein temps: a temps partiel: 6. EMPLACEMENT: (1) Centre—yule (3) Ville/village (2) Banlieue (4) Region non—incorporée 7. OFFREZ—VOUS: (1) Hémodialyse (4) internat (2) Clinique de desintoxication (5) postes de residence (3) Clinique de MTS et SIDA 8. A QUAND REMONTE VOTRE DERNIERE ACCRDITATION? Date Agence Statut Page 100 Effectiveness of Infection Control Strategies PRCAUTIONS ILIMENTAIRES/ISOLATION DES SUBSTANCES ORGANIQUES Est—ce que votre établissement a formellement décidé dadopter ou de rejeter les Precautions élémentaires ou l’Isolation des substances organiques? Laquelle des deux strategies a été adoptée ou rejetée? Quels facteurs ant influence cette decision? Quels avantages et queues difficultés prévoyez—vous dans limplantation de ces strategies? Avez—vous des informations concernant les coGts dimplantation ou d’opération de ces strategies comparativement aux programmes dIsolation spécifique par categories ou maladies? Indépendamment des politiques, croyez—vous qu’au moms 50% du personnel affecté aux salles remballe les aiguilles utilisées? Quel type de contenant est utilisé pour disposer des aiguilles et comment ces aiguilles sont—elles transportees de lendroit dutilisation a lendroit oü on en dispose (remballées, placées sur des plateaux, piquées dans des blocs de caoutchouc mousse, portées dans les mains, etc.)? Queues informations supplémentaires voudriez—vous recevoir, au besoin, pour pouvoir recommander ou déconseiller lusage des Precautions élémentaires? .pour recommander ou déconseiller lusage de lIsolation des substances organiques? Page 101 Effectiveness of Infection Control Strategies POLITIQUES COURANTES: Pour chaque politique. priere de placer on X dans la case ‘OPI cu ‘ION dans chacune des colannes pour indiquer si vous aye: dëjà: RE1J LA PUBLICATION REVtJ LA PUBLICATION ADOPT LA POLITIQUE POLITIQUE EW SOURCE: OUI NON OUI NON OUI-DATE (rn/a) NON Les Precautions élémentaires ne requiCrent plus ‘avertissernent sur les étiquettes des échantilions. CANADA DISEASES WEEKLY REPORT 1987; 1333 Layer les mains n’est pas nécessaire aprés avoir enlevé des gants portés pour empécher le contact avec le sang, les sécrétions, les membranes rnuqueu— ses ou les lesions, a moms que les mains ne soient visiblernent souillées. ANN INTERN MEl) 1987;107:243 Chambre privée reconirnandée pour pneumonic a staph. 1983 CDC “GUIDELINE FOR ISOLATION PRECAUTIONS IN HOSPITALS” Chambre privée n’est pas nécessaire pour pneumonic a staph. 1985 HEALTH & WElFARE CANADA ISOLATION AND PRECAUTION TECHNIQUES” INFECTION CONTROL GUIDELINES Bien emballer tout déchet ou linge pour prévenir les fuites; les cas d’infection ne nécessitent pas d’autre étiquetage, ni sacs doubles, ni maniement special. ASEPSIS 1986;8(4):2 Les travailleurs de la sante doivent étre renseignés sur les procedures de contràle des infections afin de prévenir la transmission des agents pathogènes par le sang; on doit aussi les aviser d ‘utiliser ces procedures pour tous les patients. N EIGL J MED 1986;315:1562 Les Precautions élémentaires ne s’appliquent pas aux excrements, urine, sécrétions nasales, larmes, expectorations, transpiration, salive, ou lait de fenuie a moms que ceux-ci ne contiennent du sang de facon visible. NMWR 1988;37(24):377 Voulez—vous recevoir les résultats préliminaires de cette étude? OUI NON Voulez—vous participer aux étapes subséquentes de cette étude? OUI NON Page 102 Effectiveness of Infection Control Strategies Appendix 3: Nurses’ Questionnaire Forms English Version French Version Expected Responses, References and Question Pairings Page 103 Effectiveness of Infection Control Strategies TO: NURSING STAFF MEMBERS FROM: David Birnbaum, MPH RE: INFECTION CONTROL PRACTICES SURVEY INTRODUCTION: My work toward a Ph.D. at University of British Columbia, supported by a Fellowship from the National Health Research and Development Program of Health and Welfare Canada, involves researching the effectiveness of several different approaches to infection control measures. Your facility has elected to participate in this national survey; your help in answering this confidential questionnaire will be greatly appreciated. Published results will not identify individual facilities nor staff members by name. You have been selected at random to receive a questionnaire. Please respond to every statement but do NOT write your name on the form. You are free to decline without repercussions if you do not wish to participate; to decline, please simply return the blank form. PLEASE CIRCLE A NUMBER ‘it) INDICATE WHErHER YOU (STRONGLY) AGREE, DON’T KfW, OR (STRONGLY) DISAGREE WITH EACH OF THE FOLLOWING STATEMEITrS: STRONGLY DON’T DIS- STRONGLY STATE1FI AGREE AGREE KNOW AGREE DISAGREE COMMEIS (OPTIONAL) 1. Risk of AIDS and hepatitis B are equal: nst needlestick exposures lead to infection with either disease. 1 2 3 4 5 2. In order to implement necessary “isolation” precautions, patients should be screened for AIDS and hepatitis B upon admission. 1 2 3 4 5 3. This hospital’s policies require a special warning label on laboratory specimens from patients with AIDS or viral hepatitis. 1 2 3 4 5 4. The primary purpose of “Body Substance Isolation” is to protect healthcare workers frc& AIDS and hepatitis B in the workplace. 1 2 3 4 5 5. Hepatitis B virus in blood that has dried on environmental surfaces may still be infectious. 1 2 3 4 5 6. All healthcare workers who receive three properly administered doses of hepatitis B vaccine will gain life—long immunity. 1 2 3 4 5 7. I have received a complete series (3 doses) of hepatitis B vaccine. 1 2 3 4 5 8. Body Substance Isolation is a system for infection precautions that eliminates the need for isolation categories (Strict, Enteric, etc.) except for one category for airborne ccemunicable infections. 1 2 3 4 5 Page 104 Effectiveness of Infection Control Strategies STRONGLY DON’T DIS- STRONGLY STATEY1ENT AGREE AGREE KNOW AGREE DISAGREE CONNENTS (OPTIONAL) 9. Needlestick injury is the single most significant source of occupational infection with hepatitis B or. HP! among healthcare workers. 1 2 3 4 5 10. Used needles should be recapped innediately after use with patients to prevent needlestick injury. 1 2 3 4 5 11. This hospital ‘s policies prohibit recapping of used disposable needles. 1 2 3 4 5 12. The risk of needJ.estick injury in manipulating the connections within IV lines (eg: mini-bag, heparin lock use, etc.) is higher than the risk of injury in giving injections with hypodermic syringes. 1 2 3 4 5 13. A significant proportion of needlestick injuries result from missing or penetrating a cap while recapping used syringe needles. 1 2 3 4 5 14. I have received instruction during the past year on this hospital’s policies for safe handling ofsharps. 1 2 3 4 5 15. When suctioning, a single sterile glove is worn on the douinant hand to protect the patient from infection. 1 2 3 4 5 16. Handwashing is I necessary after removing gloves unless the hands are visibly soiled. 1 2 3 4 5 17. This hospital’s policies require gloving for any activity likely to cause contact with blood, secretions, excretions, mucous membranes, or open lesions. 1 2 3 4 5 18. The primary purpose of gloving under “Universal Precautions” is to protect patients from bacterial and viral cross—infections. 1 2 3 4 5 19. Gloves do NOT provide any real protection since they leak and there isn’t evidence showing that their use prevents transmission of infection. 1 2 3 4 5 20. Gloves may be worn from patient to patient if gloved hands are washed between patients, 1 2 3 4 5 21. I have received instruction during the past year on this hospital’s policies for proper use and disposal of gloves. 1 . 2 3 4 5 Page 105 Effectiveness of Infection Control Strategies STRONGLY DON’T DIS- STRONGLY AGREE AGREE KNOW AGREE DISAGREE CONMFI’ITS (OPTIONAL) 22. Universal Precautions and Body Substance Isolation require that vinyl or latex gloves be iorn for every patient—care activity. 1 2 3 4 5 23. Most studies have shown that nurses wash their hands adequately between patient care activities. 1 2 3 4 5 24. Staff members who are !I’ imune to cbickenpox may safely care for patients with chickenpox or herpeszoster. 1 2 3 4 5 25. I have received in-service instruction frctn this hospital explaining the application of “Universal Precautions”. 1 2 3 4 5 26. Universal Precautions or Body Substance Isolation eliminates a need for “bithazard” warning labels on specimens frctn infected patients. 1 2 3 4 5 27. Everything discarded in any “isolated” patient’ s roon should be incinerated or sterilized as “infectious waste”. 1 2 3 4 5 28. Universal Precautions prohibits disposal of any patient wastes in a x*iiminity’s sanitary landfill. 1 2 3 4 5 29. This hospital’s infection control measures are practical, effective, and well-documented. 1 2 3 4 5 30. The primary purpose of Universal Precautions is to protect patients and staff fron all types of nosoconial infections. 1 2 3 4 5 31. I have had one or ire needlestick injuries at this hospital during the past 30 days. 1 2 3 4 5 32. This questionnaire was difficult to understand. 1 2 3 4 5 Please return, whether completed or not, in the envelope provided. Page 106 Effectiveness of Infection Control Strategies A: Membres du Personnel/Infirmières DE: David Birnbaum, MPH SUJET: Enquête sur les Strategies pour Contrôle d’Jnfection INTRODUCTION: Mes travaux envers un Ph.D. a l’université de la Colombie Brittanique, appuyés par un bourse du Programme National de Recherche et de Dèveloppement en Matière de Sante, Sante et Bien—être Social Canada, impliquent une recherche sur l’efficacité d’un certain nombre de strategies différents utilisées pour le contrôle d’infection. Votre section de service a choisi de participer a ce questionnaire national; nous apprécions beaucoup votre collaboration en répondant a ce questionnaire confidentiel. La publication des résultats se gardera d’identifier, soi les sections de service particulières ôu les membres du personnel. Votre nom a été selectionné a la pige pour recevoir ce questionnaire. Veulllez s.v.p. répondre a chacune des questions, mais prier de ne pas écrire votre nom sur le formulaire. Le choix de répondre a ce questionnaire est facultatif et sans repercussion, quel que soi ce choix. Si vous optez de ne pas y répondre, veuillez renvoyer le formulaire comme tel. V1JILU2 2F21 LE NLO DThIThN ‘,1YIRE CHODC DE PRICE: (1) BSIAENF D’ACCORD, (2) D’ACCORD, (3) NE SAIS PAS, (4) PAS D’ACCC*D aJ (5) DEFINIvFNP PAS D’ACRD PC*JR CHACUN DL 2’ccs SUIVANTS. NE DFD1VEN ABSOLUNN SAIS PAS D’AccORD PAS D’AcD iNfAIRFS 1. Les risques d’ enquérir le CIDA i 1 ‘hépitate B sont équitables: la plupart des ouvertures d’aiguilles sont précurseurs de l’infection de soi l’une ou l’autre des maladies. 1 2 3 4 5 2. Afin d’implanter les precautions d’isolation nécéssaires, les patients devraient subir un examen scrutaire pour determiner 1 ‘existence de CIDA et d’hépatite B avant admission. 1 2 3 4 5 3. Les politiques cle cet hopital exigent une etiquette d’avertissement identifiant les spéciiuèns de laboratoire provenant de patients avec le CIDA ou l’hépatite viral. 1 2 3 4 5 4. Le but primrdial d’ Isolation de Substance Organicjues est de protéger ceux et celles au service de la santée, de l’infection du CIDA et d’hépatite B dans le milieu du travail. 1 2 3 4 5 5. Le virus d’hépatite B pout être encore infectueux même s’ ii se trouve dans le sang asséché sur une surface environnementale. 1 2 3 4 5 Page 107 Effectiveness of Infection Control Strategies NE DFINITIVEMEN ABSOUJME’1T SAIS PAS EK)NCS D’ACCORD PAS D’ACCORD CX)MMENI7JRES 6. Toute personne au service de la sante qul recoit 3 doses de vaccin Hépatite B proprement administrées est iniiunisée pour la vie. 1 2 3 4 5 7. J’ai reçu l’iinunization conplète du vaccin Hépatite B (3 doses). 1 2 3 4 5 8. L’Isolation de Substances Organiques est un système pour les precautions envers 1 ‘infection, qui élimine la nécéssité de categories d’isolation (eg. STRIcT, ENTERIC, etc.) sauf une catégorie d’infection transmissible aéroportée. 1 2 3 4 5 9. Dans ce métier, le foyer d’infection avec l’hépatite B ou le liv qui est le plus significatif entre ceux ou celles au service de la sante est la bléssure d’aiguille. 1 2 3 4 5 10. Les aiguilles usager doivent étre recapsulées inédiatement suivant leurs usage sur le patient af in de prévenir toute blêssure d’aiguille. 1 2 3 4 5 11. Les politiques de cet hâpital interdisent le recapsulement des aiguilles—à—jeter usagées. 1 2 3 4 5 12. Le risque de blessure d’aiguilles, subit durant la manipulation des connections de ligne IV contrairement au même risque provenant de picpres, est beaucoup plus élevé. 1 2 3 4 5 13. Une proportion considerable de blessure d’aiguilles sont le résultat de la pénétration de la capsule ou de manquer la capsule avec l’aiguille durant le recapsulage. 1 2 3 4 5 14. Durant cette année passée j ‘ai reçu de l’instruction des politiques de cet hôpital envers le maniement des objets a pointe aigüe. 1 2 3 4 5 15. Pour protéger le patient contre l’infection, ii est nécéssaire de porter qu’ un gant sterile sur la main principale durant 1 ‘aspiration. 1 2 3 4 5 16. Aprés avoir enlevé les gants, ce n’est pas nécéssaire de se layer les mains a nin que les mains soient visiblement souillées. 1 2 3 4 5 Page 108 Effectiveness of Infection Control Strategies NE DFINITIVEMENT ABSOLUMENT SAIS PAS EN0NS D’ACcORD PAS D’ACCORD CO!4MENTMRES 17. Les politiques de cet hâpital reguient que, pour toutes activitées ou le contacte avec le sang, les sécrétioris, les excretions, les membranes muqueuses, ou les blCssures ouvertes est possible, les gants doivent ètre portés. 1 2 3 4 5 18. Le but primordial des “Precautions lémentaires” gui éxige qu’on portent les gants, est de protéger les patients contre les infections—croisées viral et bactériens. 1 2 3 4 5 19. Les gants, puisque us coulent, n’offrent pas de vrai protection et ii n’a pas d’évidence que l’usage des gants prévient la transmission des infections. 1 2 3 4 5 20. On peut porter les gants de patient a patient si on se laves entre chaque patient. 1 2 3 4 5 21. Durant cette année passée jt ai reçu de l’instruction des politiques de cet hópital envers l’usage et la disposition de gants. 1 2 3 4 5 22. “L’ Isolation de Substances Organiques” et les “Precautions lémentaires” requient que je porte de gants de vinyle ou de latex pour chaque activitée avec mes patients. 1 2 3 4 5 23. Les infirmières se lavent les mains suffisament bien entre chaque patient, ce qui est indiqué par la plupart des etudes. 1 2 3 4 5 24. Tout personnel de l’hâpital gui ne sont pas uTaTunisé contre la varicelle peuvent quand même soigner, sans risque, ceux gui ont la varicelle ou les herpes zoster. 1 2 3 4 5 25. J’ai deja reçu de cet hôpital des instructions expliquant 1 ‘application des “Precautions lémentaires”. 1 2 3 4 5 26. Les “Precautions Elénientaires” ou “l’Isolation des Substances Organigues” élmniinent le besoin d’ etiquette d ‘ avertissement “bio—hazard”, pour les spécimèns des patients infectés. 1 2 3 4 5 27. Tout objets abandonnés dans la chambre “isolée” d’un patient, devraient êtres incinérés ou stérilizés ccanme “déchéts infectueux”. 1 2 3 4 5 Page 109 Effectiveness of Infection Control Strategies NE DFINITIVEM\TT ABSOUJMENT SAIS PAS EN0NCS D’ACCORD PAS D1ACCORD CONMENTAIRES 28. Les “Precautions 1érnentaires’ empêchent que toutes ordures ou déchéts des patients soient enlevés au terrain dépotoir sanitaire de la coiunauté. 1 2 3 4 5 29. Les mesures utilisés pour le controle d’infections de cet hopital sont éfficace, pratique et bien documentées. 1 2 3 4 5 30. Le but prordia1 de les “Precautions E].émentaires” est de protéger les patients et le personel de ],‘hopital contre tout les types d’infections nosocomiales. 1 2 3 4 5 31. Durant les derniers trente jours a cet hôpital, j’ai subis une blessure d’aiguille. 1 2 3 4 5 32. J’ai eu de la difficultée a comprendre ce questionnaire. 1 2 3 4 5 Veuillez renvoyer ce formulaire dans Fenveloppe fourni, rempli ou non. Page 110 Effectiveness of Infection Control Strategies QUESTION: EXPECTED REPLY REFERENCE PAIR 1 Risk of AIDS and hepatitis 3 are equal: most needlestick exposures lead to DISAGREE infection vith either disease. 2 In order to implement necessary “isolation” precautions, patients should be DiSAGREE 2 26 screened for AIDS and hepatitis S upon admission. 3 This hospital’s policies require a special yarning label on laboratory (site specific) — specimens from patients vith AIDS or viral hepatitis. 4 The primary purpose of “Body Substance Isolation” is to protect healthcare DISAGREE 3 30 yorkers from AIDS and hepatitis B in the vorkpiace. 5 Bepatitis B virus in blood that has dried on environmental surfaces may AGREE still be infectious. 6 All healthcare yorkers vho receive 3 properly administered doses of DISAGREE 5,6 24 hepatitis B vaccine vill gain life—long immunity. 71 have received a complete series (3 dosesi of hepatitis B vaccine. (site specific) — 0 S Body Substance Isolation is a system for infection precautions that eliminates AGREE 3 18 the need for isolation categories (Strict, Enteric, etc.) except for one category for airborne communicable infections. 9 Needlestick injury is the single most significant source of occupational AGREE 78 12 infection vith hepatitis B or BIY among healthcare yorkers. 10 Used needles should be recapped immediately after use vith patients to prevent DISAGREE 7,8,13,16, 13 needlestick injury. 11 This hospital’s policies prohibit recapping of used disposable needles. (site specific) — 12 The risk of needlestick injury in manipulating the connections vithin IV lines AGREE 9 9 (eg: mini—bag, beparin lock use, etc.) is higher than the risk of injury in giving injections vith hypodermic syringes. 13 A significant proportion of neediestick injuries result from missing or AGREE 9 10 penetrating a cap nile recapping used syringe needles. 141 have received instruction during the past year on this hospital’s policies (site specific) — 0 for safe handling of sharps. 15 ben suctianing, a single sterile glove is yarn on the dominant band to protect DISAGREE 10 19 the patient from infection. 16 Bandvashing is NOT necessary after removing gloves unless the hands are DISAGREE 11 23 visibly soiled. 17 This hospital’s policies require gloving for any activity likely to cause (site specific) 0 contact vith blood, secretions, excretions mucous membranes, or open lesions. 18 The primary purpose of gloving under ‘Universal Precautions” is to protect DISAGREE 12 8 patients from bacterial and viral cross—infections. 19 Gloves do NOT provide any real protection since they leak and there isn’t DISAGREE 12,13 15 evidence shoving that their use prevents transmission of infection. 20 Gloves may be vorn from patient to patient if vashed betveen patients. DISAGREE 3,11,12,13 22 211 have received instruction during the past year on this hospital’s policies (site specific) — 0 far proper use and disposal of gloves. 22 Universal Precautions and Body Substance Isolation require that vinyl or latex RISAGREE 12,13 20 gloves be yarn for every patient—care activity. 23 Most studies have shovn that nurses vash their hands adequately betveen patient DISAGREE 14,15 16 care activities. 24 Staff members no are NOT immune to chickenpox may safely care for patients DISAGREE 16 6 vith chickenpox or herpes zoster. 251 have received in—service instruction tram this hospital explaining the (site specific) — 0 application of “Universal Precautions”. 26 Universal Precautions or Body Substance Isolation eliminates the need for AGREE 12 2 “biohazard” yarning labels on specimens from infected patients. 27 Everything discarded in any “isolated” patient’s room should be incinerated or DISAGREE 17 20 sterilized as “infectious vaste”. 28 Universal Precautions prohibits disposal of any patient vastes in a community’s DISAGREE 17 27 sanitary landfill. 29 This hospital’s infection control measures are practical, effective, and yell— AGREE - 0 documented. 30 The primary purpose of Universal Precautions is to protect patients and staff DISAGREE 1,13,12 4 from all types of nosocomial infections. 311 have had one or more needlestick injuries at this hospital during the past 30 days. — — 0 32 This computer program vas difficult to use. — - 0 Page 111 Effectiveness of Infection Control Strategies References for Nurses’ Questionnaire 1. Hughes JM: Universal Precautions, CDC Perspective. OCCUPATIONAL MEDICINE STATE OF THE ART REVIEWS 1989;4:13-27. 2. Gerberding JL, UC San Francisco Task Force. Recommended Infection—Control Policies for Patients with Human Immunodeficiency Syndrome, an Update. N ENGL J MED 1986;315(24):1562—4 3. Lynch P, Jackson MM, Cummings MJ, et al. Rethinking the Role of Isolation Practices in Prevention of Nosocomial Infections. ANN INTERN MED 1987;107;243—6. 4. Bond WW, Favero MS, Petersen NJ, et al. Inactivation of Hepatitis B Virus by Intermediate — to —High Level Disinfectant Chemicals. J CLIN MICROBIOL 1983; 18(3) :535—8. 5. Hadler SC, Francis DP, Maynard JE, et al. Long—Term Immunogenicity and Efficacy of Hepatitis B Vaccine in Homosexual Men. N ENGL J MED 1986;315(4):209—14, 6. Barnas GP, Hanacik U. Hepatitis B Vaccine, Persistence of Antibody Following Immunization. INFECT CONTROL HOSP EPIDEMIOL 1 988;9(4): 147—50. 7. Elmslie K, Mulligan L, O’Shaughnessy MV. Occupational Exposure to the Human Immunodeficiency Virus Among Health—Care Workers in Canada. CDWR 1 988;14(43): 197—200. 8. Marcus R, CDC Cooperative Needlestick Surveillance Group. Surveillance of Health Care Workers Exposed to Blood from Patients Infected with the Human Immunodeficiency Virus. N ENGL J MED 1988;319:1118—23. 9. Jagger J, Hunt EH, Brand—Elnaggar J, et al. Rates of Needle—Stick Injury Caused by Various Devices in a University Hospital. N ENGL J MED 1989;319(5):284—8. 10. INFECTION CONTROL GUIDELINES, PREVENTION OF NOSOCOMIAL PNEUMONIA. HEALTH AND WELFARE CANADA, 1988, p. 41. 11. Doebbeling BN, Pfaller MA, Houston AK, et al. Removal of Nosocomial Pathogens from the Contaminated Glove, Implications for Glove Reuse and Handwashing. ANN INTERN MED 1988;109(5):394—8. 12. LCDC. Universal Precautions, Report of a Consensus Committee Meeting. CDWR 1989;15(5):23—28. 13. LCDC. Update— Universal Precautions for Prevention of Transmission of Human Immunodeficiency Virus, Hepatitis B Virus, and Other Bloodborne Pathogens in Health—Care Settings. CDWR 1988;14(27):1 17—24. 14. Fox, MK, Langner SB, Wells RW. How Good Are Handwashing Practices? AM J NURS 1974;74(9):1676—8. 15. Albert RK, Condie F. Hand—Washing Patterns in Medical Intensive—Care Units. N ENGL J MED 1981;304(24):1465—66. 16. INFECTION CONTROL GUIDELINES, OCCUPATIONAL HEALTH IN HEALTH CARE FACILITIES. HEALTH AND WELFARE CANADA, 1986. p.43 17. Canadian Standards Association. HANDLING OF WASTE MATERIALS WITHIN HEALTH CARE FACILITIES. CAN/CSA—Z3 17.10—88 Page 112 Effectiveness of Infection Control Strategies Appendix 4: Efficacy of MIDI for Epidemiologic Typing of Staphylococcus epidermidis David Birnbaum, MPH With the assistance of: Leona Ayers, MD John Boyce, MD Loreen Herwaldt, MD Don Low, MD Michael Noble, MD Michael Pfaller, MD Robert Sherertz, MD Anthony W. Chow, MD Page 113 Effectiveness of Infection Control Strategies ABSTRACT Lack of an adequate typing system has hampered our understanding of the epidemiology of infections caused by coagulase—negative staphylococci (CNS). CNS have become recognized as important nosocomial pathogens, and the principal cause of infections associated with invasive devices. Sensitive, specific and convenient methods are needed to evaluate whether implementation of guidelines for infection control reduce the risk of nosocomial infections from CNS and other pathogens. Existing typing methods are either not convenient for use in most hospital laboratories or lack adequate specificity to distinguish between strains. The Microbial Identification System (MIDI, Microbial ID Inc., Newark, Delaware), a semi—automated system for fatty acid methyl ester (FAME) analysis, shows considerable promise for clinical and epidemiologic applications. Its predictive accuracy and reliability were tested using epidemiologically— related and replicated CNS isolates as well as CNS from epidemiologically unrelated clinical infections. These isolates were obtained from five established hospital culture collections in diverse geographic locations. Two—hundred isolates were fully characterized in five days by one person using MIDI, and results were consistent with those produced by more expensive and time—consuming conventional typing methods. MIDI, an attractive alternative to molecular microbiology methods, may offer important advantages to hospital epidemiologists and infection control programs. Page 114 Effectiveness of Infection Control Strategies INTRODUCTION Universal Precautions (UP) is an expensive strategy for preventing occupational infection of healthcare workers with bloodborne pathogens. The nation—wide cost of UP per human immunodeficiency virus infection prevented is estimated at between one—million and ten—million dollars.1 2 It has been suggested that UP or another strategy, Body Substance Isolation (BSI), might also reduce patients’ risk of nosocomial infections, thus improving the cost— effectiveness of these strategies. However, the few studies of compliance or effectiveness under UP or BSI that are available present contradictory findings. Therefore, although UP and BSI advocate gloving for patient—care activities, its value as an infection control measure is not precisely known. Methods to trace the sources of specific infections are needed to further our understanding. Staphylococcus epidermidis, for example, is clearly the most common pathogen in intravascular (IV) device—associated sepsis, but the relative importance of different routes of infection is uncertain.3 If entry—site skin flora migrating along cannulae cause most IV CNS infections, then infection control measures must focus on antiseptics, time limits for site use and minimizing trauma of the insertion site. If contamination of IV hubs by exogenous flora is more frequent, then a focus on asepsi, including use of gloves under either UP or BSI, may reduce the risk of common source or cross— infection. Evidence supporting the former view may be biased by use of microbiologic rather than clinical definition of infection in some studies. Further, it is not difficult to imagine that variation in hospital practices would lead to variation in the extent of hub contamination at different times or places. A convenient typing system would allow individual hospitals to monitor the origin of such infections, periodically adjusting the emphasis of their own Page 115 Effectiveness of Infection Control Strategies infection control program accordingly. The basis for an epidemiologically useful typing system is to exploit documented species diversity, but this is often comparable to hitting a moving target with tools of uncertain precision, accuracy or reliability. Existing typing systems are not adequate for tracing the origin of nosocomial ONS infections.4 Fatty acid methyl ester (FAME) analysis as a qualitative pattern—recognition method is well—established for species—level identification (eg: anaerobes). Eerola and Lehtonen recently demonstrated its reliability in distinguishing between species of different aerobic genera as well as between strains within species, but noted that different univariate correlation methods used for data analysis are not equiva1ent. Subsequent work suggested the future ability to discriminate between epidemiologically related and unrelated strains.6 MIDI (Microbial ID Inc., Newark, Delaware) automates quantitative analysis of over 200 fatty acid metabolic products and comparison with proprietary database libraries by multivariate statistical methods. New library entries can be created by individuals when isolates with an unrecognized pattern are encountered, and subsequent samples are automatically compared to this updated library. MIDI establishes species—level identifications through principal component analysis of ratios of FAME peak areas. This multivariate, quantitative approach promises superior ability over simple pattern recognition to differentiate between organisms. In addition to providing genus—species identifications, MIDI software can also display the degree of relatedness of isolates on two—dimensional principal component plots and on cluster analysis dendrograms. However, MIDI has not been applied to epidemiologic typing of CNS. Since it may offer advantages to both clinical laboratories and hospital epidemiologists, its discriminatory power, predictive accuracy, intra— and inter—laboratory reliability Page 116 Effectiveness of Infection Control Strategies for subspecies typing of CNS need to be documented. MATERIALS & METHODS: DESCRIPTION OF ORGANISMS One—hundred and eighty—three well—characterized coagulase—negative staphylococci (eNS) from clinical specimens were obtained from culture collections in five geographically distinct areas. Their identification and antimicrobial susceptibility profile were determined in the contributing laboratories using conventional methods approved by the National Committee for Clinical Laboratory Standards (NCCLS). Identifications were confirmed subsequently by one of us (MP) using the scheme of Kloos and Schielfer. Some of these collections have been described elsewhere.7 8 Among the 183 are six groups containing epidemiologically related isolates: ten S. haemo]yticus blood culture isolates from neonates in Ontario; three pairs of matching blood and intravascular cannula tip S. epidermidis isolates from British Columbia; five S. epidermidis isolates from an outbreak of surgical wound infections attributed to a surgeon’s hand flora in Rhode Island and twelve consecutive S. epidermidis isolates from one immunosupressed patient in Iowa. Their epidemiologic relatedness was assessed on the basis of the following criteria, in descending order of importance (see Table 23): 1. Epidemiologic evidence of time—space clustering 2. Matching biotype/susceptibility profile a) No differences = no evidence that isolates are different b) 1 difference = isolates might be different c) 2 differences = isolates are different 3. Molecular methods, if done, show no differences a) Plasmid Profile b) Restriction endonuclease analysis (REA) c) Hybridization (probe or DNA [RFLPI) Other isolates obtained from each collection differ from each other by conventional microbiological typing and/or lack of epidemiologic suspicion of Page 117 Effectiveness of Infection Control Strategies common—source or cross—infection relatedness among them. The remaining 155 isolates were judged to be epidemiologically unrelated by methods that meet or exceed current standards of infection surveillance practice. Forty—eight unrelated blood culture isolates collected over a 6 month period in one Ontario children’s hospital exhibited unique combinations of biotype, susceptibility profile and plasmid profile, and no evidence of time—space clustering. Fifty—seven unrelated blood culture isolates from a university hospital in Iowa were unique in their combined biotype, susceptiblity profile, slime production, synergistic hemolysis, plasmid profile and restriction digest patterns. Forty—two unrelated blood culture isolates in a British Columbia university hospital were selected from a collection spanning 3 years; they were considered unrelated episodes on the basis of no time—space clustering. Three isolates from intravascular lines in a North Carolina university hospital were also judged to be unrelated, in spite of comparable biotype and susceptibilty profiles, on the basis of epidemiologic assessment. The majority of these isolates, primarily Staphylococcus epidermidis, meet CDC criteria for clinical significance9. Twenty—six of the 183 were blood culture contaminants (included to study how closely they would be related to clinically—significant isolates). One isolate was replicated eighteen times (group #7) to test intra—laboratory reliability. The entire set of 200 randomly— numbered clones was analyzed blindly and independently in two facilities with established MIDI systems (under supervision of Microbial ID Inc. staff in their laboratory, and in a university hospital clinical laboratory) to test inter— laboratory reliability. Media inoculation was done in Class II laminar airflow hoods, and colony morphology was inspected on subcultures (to check for contaminants) immediately after receipt of isolates from contributing laboratories Page 118 Effectiveness of Infection Control Strategies and again just prior to MIDI analyses. MIDI TECHNIQUE Analysis was conducted in accordance with MIDI instructions.10 Briefly, isolates were quadrant—streaked onto trypticase soy agar (TSA) plates (BBL) and harvested in log—phase growth after 24 (±2) hours’ incubation at 28CC in air. Approximately one 4mm loop—full of bacteria was scraped for each sample. Each sample was then saponified, methylated, extracted and cleaned before removing its organic layer for injection into MIDI’s gas chromatography system. Calibration standards and a negative control blank were run with each batch, and one positive control specimen (Xanthomonas maltophilia, ATCC 13637) was run each day. MIDI’s aerobic bacteria library (Ver. 3.30) was used for interpretation, Samples with suboptimally low gas chromatography results (total peak area <80,000 or <85% of peak area used by the naming algorithm) were repeated after concentration by evaporation. STATISTICAL ANALYSIS MIDI computes an index for each isolate through principal component analysis of ratios of cellular fatty acid content. Cluster analysis of these indices was applied’1 with Euclidian distances calculated by the simple and Ward’s’2 linkage methods. Empirically, the replicated (group #7) isolates’ joining distances were examined to determine an optimal strain—level joining distance. The MIDI system software and SYSTAT (version 4.1, Systat Inc., Evanston IL) were used for statistical analysis. Discriminatory power was calculated as Simpson’s Index, the probablity that two isolates selected at random would be placed into different typing categories.13 Sensitivity, specificity, positive and negative predictive accuracy were evaluated by comparing MIDI’s predictions with the known related or unrelated nature of Page 119 Effectiveness of Infection Control Strategies isolates. RESULTS All 200 isolates were typable and their analysis was completed in 5 days by one of us (DB). Nearly two—thirds of an inexperienced operator’s first batch of extracts had low peak areas and required concentration, but subsequent batches rarely suffered this problem. A critical distance to distinguish between related and unrelated isolates was established emperically by examining the Euclidian distance at which known epidemiologically—related isolates joined. Group #7 was taken as the ‘gold standard” for clonal origin. These replicated isolates all joined at 5.4 units, but exhibited independent clustering at 4.5 units on a dendrogram generated by Ward’s method. Thus, any isolates joining at less than 4.5—5.4 units could be considered clustered into the same typing category, whereas isolates joining at more than 5.4 units would be assigned into different categories. This is illustrated in Figure 12. Single and Ward’s linkage methods yielded similar groupings. At least 46 typing categories were readily apparent, with a Simpson’s Index of 0.93 (Table 24). Approximately half of the categories contained a single isolate. There are seven groups of related isolates in the test set. Group seven was created artificially by replicating one isolate eighteen times. MIDI found three clusters joined at 0.7—2.1 units, and linkage of these clusters at 4.5—5.4 units. The former range is consistent with previous experience for repeated analysis of the same isolate (personal communication, Myron Sasser), and the possibility of a mixed culture was noted. Group one consisted of 10 blood culture isolates from one neonatal nursery, identified by the contributing laboratory as S. haemolyticus with identical Page 120 Effectiveness of Infection Control Strategies susceptibility profile, restriction endonuclease pattern and hybridization to three drug—resistance probes. This resistant strain was endemic in several adjacent hospitals, the affected infants had overlapping hospitalization dates during a 5 month period, but there was no conclusive evidence to establish or rule out common source or cross—infection. MIDI identified two isolates (obtained within three days of each other) as related to each other and to a third (joined at 1.9 Euclidian distance units) and fourth (at 5.4 units). Group two consisted of matching blood culture and intravascular cannula isolates from a single patient. MIDI placed these two (and other epidemiologically—unrelated isolates) in a single category. This patient had three CNS isolated from an intravascular line; only one matched the blood isolate’s susceptibility profile. MIDI correspondingly typed the isolates with matching profiles as related and the other two as unrelated. The correctly paired isolates joined at 2.6 Euclidian distance units, and subsequently were identified as S. epidermidis whereas the other two cannula isolates were confirmed as S. intermedius and S. auricularis. On the basis of susceptibility profile differences, the two related isolates could be distinguished from most of the epidemiologically—unrelated isolates in this MIDI typing category. Group three similarly consisted of paired blood and cannula isolates from another patient. MIDI placed these two and other epidemiologically—unrelated isolates in a single category. The correctly paired isolates joined at 1.2 Euclidian distance units. On the basis of susceptibility profile differences, four subcategories correctly separated the two related isolates from three mutually unrelated isolates. Group four also consists of paired blood and cannula isolates from one patient. These were correctly matched, again with unrelated isolates as well, at Page 121 Effectiveness of Infection Control Strategies a distance of 3.8 units, and susceptibility profile differences created subcategories correctly separating related from unrelated isolates. Group five consisted of S. epidermidis from a surgeon’s hands, two infected surgical wounds, and two blood cultures. Temporal clustering, plasmid analysis, EcoRI restriction endonuclease digests, antibiograms and biotyping document this as a common—source outbreak. MIDI typed the four patient— isolates as related (3 joined at 1.4 units and the 4’th at 2.8) but the surgeon— isolate was in a different category (joined at 10.6 units). Susceptibility profile differences created subcategories correctly distinguishing the outbreak patient isolates from unrelated isolates. This is illustrated in Figure 12: isolates joining to the right of the distance marked as did not cluster into the typing category containing the outbreak patient isolates. Group six, a series of twelve S. epidermidis isolates from one immunosupressed patient, was identified by MIDI as two clusters and two unrelated isolates. One cluster consisted of two isolates from blood cultures drawn on the same day (joined at 2.1 distance units). The second contained eight isolates obtained over several months (joined at 4.5 units). Since the susceptibility profiles differ, at least two distinct clusters are correctly identified by MIDI for group six. DISCUSSION A “gold standard” for comparison was established by available epidemiologic and microbiologic information with clinical isolates. It is reasonable to assume that such information is valid for ruling out relatedness. However, it cannot be considered conclusive proof of relatedness when it failed to find differences: testing with another substrate or enzyme, or a more powerful method might reveal differences. MIDI’s grouping together of isolates shown by other methods Page 122 Effectiveness of Infection Control Strategies to be epidemiologically unrelated may be an error resulting from detecting taxonomically similar (but epidemiologically unrelated) strains. MIDI’s separation of isolates grouped together by other methods may be an error or may indicate that MIDI is a more powerful typing method. Although MIDI’s predictions closely paralleled the “gold standard” results, MIDI’s failure to cluster all of Group 5’s isolates into one category is of concern. The surgeon’s hand isolate had been found identical to the patient isolates by whole plasmid gels, plasmid REA and pulsed field electrophoresis analysis of chromosomal DNA. These results are promising, but further work is required to document MIDI’s accuracy MIDI conveniently accomodates large numbers of isolates, can supply a typing result for every isolate, and its material costs for complete identification are low (about $1.30 per isolate). One—tube sample preparation (saponification [sodium hydroxide in methanoll, methylation [hydrochloric acid in methanol], extraction [hexane in methyl tert—butyl ether], sample cleanup [sodium hydroxide]) and automated analysis accomodate identification of up to 45 samples per technologist—day per machine. One person can process as many as 30—50 isolates in about 4 hours, depending upon experience. Performance of gas chromatography requires an additional thirty minutes per sample. MIDI’s waste can be recycled or biodegraded. Compared to other typing systems, a relatively small amount of plastic is discarded. Glass, water and sodium chloride are the major waste products. Growth of CNS on TSA plates at 24 hours was often relatively light. Better growth might be achieved on blood agar at 37CC, but MIDI’s library for this condition is not as well established as their aerobic 28CC TSA library. Improved reproducibility with blood agar at 37 has been reported for other aerobic bacteria.14 This problem was easily overcome by using a heavier Page 123 Effectiveness of Infection Control Strategies inoculum. Streaking two rather than one TSA plate is another possible strategy when poor growth is anticipated, and offers the additional advantage of allowing an immediate repeat extraction in case a critical sample is ruined by an error in technique. Concentrating extracts for a second chromatography run, the standard procedure when MDI’s printout warns of unacceptably low peak areas, was also simple and effective: 84% of flagged” results attained acceptable peak areas after concentration. Difference in joining distance between “flagged’ results versus concentrate results (due to new peaks emerging above detection limits) changed the typing category assigned in 16% of these samples (Fig. 13). FAME analysis by gas—liquid chromatography may be particularly cost— effective for epidemiological typing of clinical or environmental isolates as compared to current alternatives. Successful application to the subspecies level has been reported with staphylococci.5’15 However, discerning epidemiologic relationships is more difficult than simply establishing taxonomic relationships. MIDI was used recently in a small study of Pseudomonas cepacia in cystic fibrosis centers; a low but promising discriminatory ability was determined among 42 isolates from 5 centers (Simpson’s index, the probability of two randomly— selected isolates being assigned to different typing categories, was O.775).16 The present study of CNS involves a larger number of isolates selected specifically to minimize the chance that they were related by unrecognized common source or cross—infection. In comparison to molecular typing methods now available to characterize isolates, MIDI promises to be a relatively powerful, rapid and inexpensive tool. ACKOWLEDGEMENTS Technical advice: Drs. Richard Mathias, Michael Kelly, Myron Sasser and Michael Schulzer. Logistical assistance: Robin Barteluk, Linda Boyken, Christine Corten, Roberta Dickenson, Shelley Scriver and Marcie Sponholtz. Page 124 Effectiveness of Infection Control Strategies Table 23: Characterization of Epidemiologically-Related Isolates by Lab of Origin GROUP NUMBER CRITERION 1 2 3 4 5 6 Epidemiology Shows Time—Space Clustering ± + + + + ± Biotype/Susceptibility Profiles Match + + + + + ± Plasmid Profile + - — — + + REA + - - - + - DNA Probe/RFLP probe - - - RFLIP — Note: + = clearly documented by contributing laboratory, ± = incompletely documented, - = not done. Page 125 Effectiveness of Infection Control Strategies Table 24: Summary of MIDI’s Typing Performance CLUSTER ANALYSIS HETHOD Ward’s Method Single Linkage THRESHOLD LIHIT Euclidean Distance 45 54* 4.6 Number of Categories Created 66 46 57 Number containing only 1 isolate 34 (52%) 21 (46%) 29 (51%) Simpson’s Index zO.96 zO.93 zO.96 Sensitivity + + + Specificity + + + Positive Predictive Accuracy + + + Negative Predictive Accuracy + + + Inter-Laboratory Agreement + + + * Group #7’s isolates all joined at 5.4 units, but exhibited independent clustering at 4.5 units. These isolates were all subcultured from isolate #1, which appeared mixed when subcultured for MIDI analysis. Further work will be required to determine whether these eighteen reference isolates were pure or mixed. It is unlikely that the threshold limit could be set any lower than 3.8, the joining distance for group #4. + Qualitative results described in text; quantitative results not yet available. + Results not yet available. Page 126 Effectiveness of Infection Control Strategies Figure 12: Section of MIDI Isolate Group ID# 167 0 100 0 100 0 101 0 73 0 91 0 109 5 108 5 107 5 129 0 169 0 110 5 120 0 159 0 166 0 128 0 74 0 57 0 48 0 111 5 Dendrogram Containing Group #5 Isolates Euclidian Distance 0.00 2.35 4.70 7.05 9.40 11.75 +-—--+——-—+—---+---.+--1-+----+---—+—-—-+---—+----+---—+ 0.00 2.35 4.70 7.05 9.40 11.75 KEY: indicates 4.5—5.4 unit joining distance limit d = epidemiologically—unrelated isolates 5 = epidemiologically—related isolates Page 127 Effectiveness of Infection Control Strategies Figure 13: Joining Distances of Repeated Assays SAMPLE TYPES C * * 10 15 20 JOINING DISTANCE Legend: C = concentrated vs. unconcentrated sample N = morphotype “a versus “b” for isolates exhibiting variants in colony size, texture or color Note: Two morphotypes of isolate #1 join at distance 9.4 Page 128 Effectiveness of Infection Control Strategies References for Appendix 4: 1. Wenzel RP. Interaction of Man and Microbe, Implications of the AIDS Epidemic for Hospital Epidemiology. AM J INFECT CONTROL. 1988; 1 6(5):214—20. 2. Stock SR, Gafni A, Bloch RF. Universal Precautions to Prevent HIV Transmission to Health Care Workers; An Economic Analysis. CAN MED ASSOC J 1990;142(9):937—46 3. Sitges—Serra A, Liñares J; Brun—Buisson C; Collignon P, Munro R. Limitations of Semiquantitative Method for Catheter Culture (letters). J CLIN MICROBIOL 1988;26(5):1074—6. 4. Birnbaum D, Kelly M, Chow AW. Epidemiologic Typing Systems for Coagulase—Negative Staphylococci. INFECT CONTROL I-IOSP EPIDEMIOL 1991; 12(5):3l 9—26. 5. Eerola E, Lehtonen 0. Optimal Data Processing for Automatic Bacterial Identification by Gas—Liquid Chromatography of Cellular Fatty Acids. J CLIN MICROBIOL 1988;26(9):1745—53. 6. Kotilainen F, Huovinen F, Eerola E. Application of Gas—Liquid Chromatographic Analysis of Cellular Fatty Acids for Species Identification and Typing of Coagulase—Negative Staphylococci. J CLIN MICROBIOL l991;29(2);315—322. 7. Sherertz RJ, Raad II, Belani A, Koo L, Rand KH, et al. Three—Year Experience with Sonicated Vascular Cathester Cultures in a Clinical Microbiology Laboratory. J CLIN MICROBIOL 1 990;28( 1):76—82. 8. Boyce JM, Potter—Bynoe G, Opal S, Dziobek L, Medeiros AA. A Common— Source Outbreak of Staphylococcus epidermidis Infections among Patients Undergoing Cardiac Surgery. J INFECT DIS 1990;161;493—99. 9. Garner JS, Jarvis WR, Emori TG, et al. CDC Definitions for Nosocomial Infections, 1988. AM J INFECT CONTROL l988;16(3);l28—40. 10. Sasser M. Technical Note #101— Identification of Bacteria by Gas Chromatography of Cellular Fatty Acids. MIDI 1990. 11. Johnson RA, Wichern DW. APPLIED MULTIVARIATE STATISTICAL ANALYSIS, 2nd Edition. Prentice Hall Inc., New Jersey. 1988. p543—72. 12. Ward JH Jr. Hierarchical Grouping to Optimize an Objective Function. AMERICAN STATISTICAL ASSOC J 1 963;58;236—44. 13. Hunter PR, Gaston MA. Numerical Index of the Discriminatory Ability of Typing Systems; An Application of Simpsons Index of Diversity. J CLIN MICROBIOL 1988:26(1 1);2465—66. Page 129 Effectiveness of Infection Control Strategies 14. Osterhout GJ, Shull VH, Dick JD. Identification of Clinical Isolates of Gram— Negative Nonfermentative Bacteria by an Automated Cellular Fatty Acid Identification System. J CLIN MICROBIOL 1991 ;29(9): 1822—30. 15. OtDonnell AG, Nahaie MR, Goodfellow DE, et al. Numerical Analysis of Fatty Acid Profiles in the Identification of Staphylococci. J GEN MICROBIOL 1985;131:2023—2033. 16. Mukwaya GM, Welch DF: Subgrouping of Pseudomonas cepacia by Cellular Fatty Acid Composition. J CLIN MICROBIOL 1989;27:2640—46. Page 130

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