Antimicrobial efficacy and durability of copper formulations over one year of hospital use Bryce, Elizabeth; Velapatino, Billie; Donnelly-Pierce, Tysha; Khorami, Hamed Akbari; Wong, Titus; Dixon, Richard; Asselin, Edouard; McGeer, Allison; Srigley, Jocelyn A.; Katz, Kevin
Objective: To evaluate three formulations of copper (Cu) based self-sanitizing surfaces for antimicrobial efficacy and durability over one year in inpatient clinical areas and laboratories. Design: Randomized control trial. Setting: Three Cu formulations were assessed a) solid alloy 80% Cu 20% Ni (integral copper), b) spray–on 80% Cu 20% Ni (spray-on) and c) 16% composite Cu-impregnated surface. Coupons (1cm2 ) of the three products and control surgical grade (AISI 316) stainless steel (SS) were inserted into gaskets and adhered onto clinical carts used in patient care areas (including Emergency and Maternity units) (n=480) and on microbiology laboratory bench workspaces (n=240). The microbial burden and assessment of resistance to wear, corrosion, and material compatibility were determined every three months. Three tertiary care Canadian adult and one paediatric/maternity hospital participated. Results: Cu formulations used on inpatient units statistically significantly reduced bacterial bioburden compared to SS at months 3 and 6. Only the integral product had significantly less bacteria compared to SS at month 12. There were no statistically significant differences in microbial burden between Cu formulations and SS coupons on microbiology laboratory benches where bacterial counts were low overall. All mass changes and corrosion rates of the formulations were acceptable by engineering standards. Conclusions: Cu surfaces vary in their antimicrobial efficacy after one year in-hospital use. Frequency of cleaning and disinfection influences the impact of copper with the greatest reduction in microbial bioburden seen in clinical areas compared to the microbiology laboratory where cleaning/disinfection occurred multiple times daily.
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