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Airborne fungi, bacteria, actinomycetes, endotoxin, and (1-->3)-ß-D-glucan in Midwest greenhouses and respiratory symptoms among workers.

Adhikari A; Olds RL; Gupta J; Wilkins JR III; Reponen T; Grinshpun SA; Indugula R; Cho KJ; Li C; Yermakov M
ASM 2010: Proceedings of the 110th American Society for Microbiology General Meeting, May 23 - 27, 2010, San Diego, CA, 2010 May; :853
Background: Greenhouse operation is an important sector of the horticulture industry, also known as the Green Industry, which accounts for nearly 2 million US jobs and $147 billion in output. There is a lack of quantitative information on the workers' exposure to microbial bioaerosols and relevant respiratory symptoms. Methods: Air samples were collected using Button Inhalable Aerosol Samplers from 3 Midwest greenhouses in winter and summer during one work shift in the 4 corners and at the center of a greenhouse compartment. Control samples were collected from offices and nearby outdoor locations. Extracts from the sampler filters were cultivated to examine airborne culturable fungi, bacteria, and actinomycetes. Endotoxin and (1-->3)-ß-D-glucan in filter extracts were analyzed by specific kinetic chromogenic LAL assays. The prevalence of respiratory symptoms among the greenhouse workers (n = 35) and controls (n = 13) was estimated by using a standardized questionnaire. The symptoms were recorded only in summer and related to overall exposure and work status in greenhouses. Results: Mean concentrations of culturable fungi and bacteria were: 429 - 3,584 CFU/m3 and 1,269 - 8,200 CFU/m3 respectively in winter, and 3,939 - 9,947 CFU/m3 and 210 - 666 CFU/m3 respectively in summer. Mean concentrations of endotoxin and (1-->3)-ß-D-glucan were: 14 - 855 EU/m3 and 8 - 71 ng/m3 respectively in winter, and 8 - 39 EU/m3 and 17 - 26 ng/m3 respectively in summer. The mean culturable actinomycetes concentrations were 14 - 127 CFU/m3 in winter and mostly zero in summer. The indoor-to-outdoor ratio exceeded 1 in most cases for all biocontaminants. The prevalence of asthma, wheezing, cough and phlegm was higher in workers (8.6, 42.9, 15.2, and 32.4%, respectively) compared to controls (7.7, 23.0, 7.7, and 7.7%, respectively); however, the differences were not statistically significant in a logistic regression model adjusted for age and gender. Conclusions: Midwest greenhouses are a significant source of workers' exposures to airborne microbial contaminants. Fungi and (1-->3)-ß-D-glucan dominate in summer whereas bacteria and endotoxin dominate in winter.
Agricultural-workers; Agriculture; Air-sampling; Airborne-particles; Aerosol-particles; Aerosols; Environmental-contamination; Microorganisms; Fungi; Bacteria; Endotoxins; Allergens; Humans; Respiratory-system-disorders; Pulmonary-system-disorders; Employee-exposure; Exposure-levels; Bioassays; Questionnaires; Health-surveys; Air-contamination; Indoor-air-pollution; Outdoors; Seasonal-factors; Allergies; Author Keywords: bioaerosols; air microbiology; respiratory symptoms
Atin Adhikari, Department of Environmental Health, University of Cincinnati, Cincinnati, OH 45267
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ASM 2010: Proceedings of the 110th American Society for Microbiology General Meeting, May 23 - 27, 2010, San Diego, CA
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University of Cincinnati
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