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Meet the microbe : why water and books don’t mix Bartlett, Karen H. 2014-05-01

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Meet the Microbe: Why Water and Books Don’t Mix Karen H. Bartlett, PhD School of Population and Public Health,  University of British Columbia  Preservation Week at UBC Library May 1, 2014 Outline What is mould/mold, fungi, mildew, decay Conditions for growth If materials are mouldy, what are the hazards? Can mould growth be prevented? Best practices to use with organic materials   Life not worth living without microbial products Cheese, yogurt Antibiotics Cured ham Kimchi, sauerkraut Miso & soy sauce Olives Beer, wine, spirits Leavened bread Sourdough bread    Neither plants nor animals – fungi have their own kingdom … Unicellular yeast cell (size range ± 10 micrometers) Filamentous fungi e.g. typical mould colony (size range of individual conidiophore ~ 100 micrometers) Mushrooms, toadstools, truffles, etc. (size of fruiting body varies – typically 1 – 20 centimeters)  Moulds “mould” = filamentous fungi Microscopic view (400 x) Mould colonies - macroscopic Image credit: K.H. Bartlett Image credit: K.H. Bartlett http://www.ppdl.purdue.edu/PPDL/images/honeysuckle_mildew2.jpg Mildew Mycologists reserve the term “mildew” for certain plant pathogens – most of the rest of us think of mildew as what damp laundry grows. Fungi: Are nature’s composters  Need oxygen Are normally free-living (saprophytic) Take in nutrients (organic compounds), oxidize compounds to provide energy and to create new compounds (chemoheterotrophs) Fungi: Optimum growth temperature Most fungi prefer ~ 4oC - ~ 30oC Some fungi prefer ≥ 35oC – 50oC Pathogenic fungi can grow at 37oC Optimum water requirements Most fungi require high water activity water Aw > 0.90 (osmophilic) Some fungi can survive on less available water Aw 0.65 – 0.90 (xerophilic) Moulds “mould” = filamentous fungi Microphotograph = 500 x magnification  Image credit K.H. Bartlett Moulds “mould” = filamentous fungi Conidia = spores) Microphotograph = 500 x magnification  Image credit K.H. Bartlett Moulds “mould” = filamentous fungi Conidiophore =  Structure that  produces spores Conidia = spores) Microphotograph = 500 x magnification  Image credit K.H. Bartlett Moulds “mould” = filamentous fungi Hyphae (mycelia) Thread-like structures that form fungal colony “mass”  Conidiophore =  Structure that  produces spores Conidia = spores) Microphotograph = 500 x magnification  Image credit K.H. Bartlett Moulds: component diagram Conidial heads (above substrate – release spores) Mycelia (aerial mycelia supports conidiophore above substrate, penetrates into substrate for nutrients) Conidia (spores – easily dispersed into air) mVOCs (volatile organic compounds = mouldy smell) Mycotoxins (secreted into the substrate) Moulds: Can reproduce either sexually or asexually – spores are spread to new substrate, germinate, and form new colonies.  Aspergillus Alternaria Cladosporium Stachybotrys Ulocladium Image credits: K.H. Bartlett Mould components that may cause human health effects structural components  spores and hyphal fragments hypersensitivity/allergy reactions Β-glucans have immunomodulating effects metabolites mycotoxins volatile organic compounds (VOCs) responsible for unpleasant odours may be cause of irritation  symptoms, sick building syndrome Image credit: K.H. Bartlett Penicillium Conditions for growth 3 key factors for mould growth spores food moisture  controlling moisture is key to preventing mould germination & growth Moisture Spores Found  everywhere! Nutrients e.g. paper, dust, fabric growth Fungi are Nature’s composters AND … Compostable material can be found everywhere! Image credit K.H. Bartlett Investigation of water leak in library Concentration ~ 6550 CFU/m3  pure culture Penicillium Image credits: K.H. Bartlett SAS = surface air sampler Pathogenicity: fungi Allergenic 96 different genera reported in literature. Cell structures 1,3 and 1,6 beta-D- glucan provoke inflammatory response Mycotoxins Penicillin (e.g. Penicillium) Aflatoxin (e.g. Aspergillus flavus) Trichothecene (e.g Stachybotrys) Pathogenicity: fungi Pathogenic or opportunistic pathogens True pathogens:  rare (luckily!) Opportunistic pathogens: e.g. Aspergillus fumigatus (common in water damaged buildings)  Mixed organic dust (farming, lumber, food processing) = combination of endotoxin (bacteria) and fungi (organic dust toxic syndrome – hypersensitivity pneumonitis) Inhalation of fungal spores Figure credit: Adapted from Phalen et al. Appl Ind Hyg 1:3-14 (1986) Respiratory organs: Head     Nose     Naso-pharnyx Neck     Trachea Lungs      Bronchi      Alveoli Allergic response: genetically determined: Allergen IgE IgE IgE  IgE IgE  IgE IgE IgE IgE IgE  IgE Non-sensitive host Sensitive host Hypersensitive host Initial exposure Repeated exposure Allergic response: genetically determined: Allergen IgE IgE IgE  IgE IgE  IgE IgE IgE IgE IgE  IgE Non-sensitive host Sensitized host Hypersensitive host Initial exposure Repeated exposure Special consideration: Aspergillus fumigatus  is pathogenic for people with compromised immune systems Chronic sinusitis associated with several fungal species  Image credit: K.H. Bartlett All fungi (actively growing) produce: Microbial Volatile Organic Compounds (VOCs)  Complex mixture of alcohols, ketones, esters, organic acids – highly identifiable as “mouldy smell”  Products of fungal metabolism   Image credit: K,H, Bartlett Personal Protective Equipment When working in a highly contaminated environment (e.g. the library after the flood): Protect eyes and mucous membranes with goggles, lungs with fitted respirator, and skin with gloves.     Tyvek suit prevents clothing from picking up spores. Image credit: Levitt-Safety Catalogue 2010 Protecting library materials: In case of flooding, organic materials need to be dried out within 48 hours. As Soon As Possible:  Freeze materials to stop further deterioration and fungal growth. Dry (freeze-drying is best procedure) When dry, control storage relative humidity to below 40%; increase air exchange rate. Clean materials with HEPA-filtered vacuum. Signs of fungal growth: Smells mouldy (active growth) Fuzzy patches, can be many colours. Swelling of paper, discolouration along edges – can be many colours. Can take a sample to culture (negative growth does not mean absence of spores, however) Image credits: K.H. Bartlett  Conclusions: Fungal spores are everywhere – they only need water to germinate and grow. Fungi will colonize any organic material if there is enough moisture available (moisture can come from atmosphere or as liquid condensate). Damage to materials is caused by fungi trying to compost them (just doing their thing!) Conclusions: If fungal spores are in high concentration, they can be harmful to humans. Take precautions when handling contaminated materials by wearing Personal Protective Equipment (PPE); use High Efficiency Particulate Air (HEPA)-filter on vacuum. Preserve collections in environments with low humidity and adequate air exchange rates.  


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