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Are we sampling for the relevant organisms?  

  • What are the site-specific conditions?

  • A combination of methods is recommended (ACGIH 1999)

    • typically, culture-based and spore trap devices

  • For culture-based sampling, more than one medium must be used (varying aw and nutrient base)

  • Selective media must be employed when the presence of particular organisms is suspected (e.g., S. chartarum)

Is the health impact of bacteria more significant?

  • “Production of Proinflammatory Mediators by Indoor Air Bacteria and Fungal Spores in Mouse and Human Cell Lines”, Environmental Health Perspectives (2003), 111:85-92

    • “Currently it is not known which components of the microbial flora are most harmful to occupants of moldy buildings.”

    • “Our working hypothesis is that bacteria…are also important in causing inflammatory and cytotoxic response.” 

  • Studied mouse and human macrophage cell lines, and human lung epithelial cell line

  • Selected commonly isolated fungi, Gram-positive and Gram-negative bacteria

  • Analyzed production of cytokines TNF-a, IL-6, IL-1b; nitric oxide; measured cytotoxicity

  • The inflammatory potency decreased in the order:

    • Pseudomonas fluorescens > Streptomyces californicus > Bacillus cereus > Stachybotrys chartarum > Aspergillus versicolor > Penicillium spinulosum

  • The cytotoxic potency decreased in the order:

    • Pseudomonas fluorescens > Stachybotrys chartarum > Streptomyces californicus > Aspergillus versicolor > Bacillus cereus > Penicillium spinulosum

 

 

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