Gram Negative Bacteria as Bioaerosols

Evaluation and Determinants of Airborne Bacterial Concentrations in School Classrooms

“…Although the categorical variables describing current moisture or water stains were associated with the likelihood of (26,27) streptomycetes, (15,17,28) or thermophilic actinomycetes, (29)(30)(31) none of these indicator organisms were found in elevated concentrations in the study classrooms. The bacterial concentrations found in this study agreed well with the Gram-positive flora found in a nonproblem middle school studied by Scheff et al (32) However, a significant Gram-negative flora was not found in our study rooms.…”

Hypothesis-based research on the causes of sick building symptoms: A design for Phases 2 and 3 of the California Healthy Building Study

“…Clearly, the hypothesis that HVAC systems are a source of bioaerosols that elicit symptoms is plausible. Microorganisms can multiply in HV AC systems, the flow of air in the HV AC systems provides a means of transport to the occupied space; and inhaled microorganisms, along with volatile microbiological by-products and other biologic materials can trigger hypersensitivity reactions such as allergic rhinitis , Hood 1990, Morey et al 1990). Even without active growth in the HV AC system, bioaerosols and other debris that have collected in an HV AC system may be resuspended when the system is disturbed vigorously or when it first is turned on after a period of non-use.…”

“…The frequency with which people report various heSith symptoms has been associated with the concentrations of specific bioaerosols, e.g., actinomycetes, other bacteria and bacterial by-products, fungi and fungal metabolites, and dust mites , Hood 1990, Jarvis 1990, Lundblad 1991, Morey et al 1990, Morey and Singh 1991, Morey et al 1986, Olenchock 1990, WHO 1990. Researchers have studied these associations by collecting air samples to assess the amounts of airborne biological material that is present and by noting the responses of the exposed people.…”

Health hazard evaluation report: HETA-94-0051-2463, Deerwood Place Office Building, San Ramon, California.

“…For example, the proliferation of such organisms as Bacillus, Flavobacterium, and Pseudomonas in stagnant water in cooling coil condensate drain pans and ventilation system liners has been identified in outbreaks of humidifier fever and hypersensitivity pneumonitis. 17,18 As a result of the information gathered in one particular study, 17 the authors proposed an upper limit of 10 5 /ml of bacteria in stagnant water; however, there are no established criteria addressing "acceptable" concentrations of fungi or bacteria in ventilation systems.…”