Molecular Analysis of Bacterial and Circovirus Bioaerosols in Concentrated Animal Feeding Operations

摘要

Respiratory illnesses are a significant cause of morbidity for individuals who work within concentrated animal feeding operations (CAFOs); however, most available information about CAFO aerobiology has derived from culture-based studies, which may detect only a small fraction of microbial diversity present. In this study, we characterized the identity, spatial distribution, and abundance of airborne microorganisms present in swine and dairy CAFOs using direct microscopy, broad-range rRNA PCR, and sequence analysis of air samples collected from within and nearby swine and cattle operations in the western United States. We report that indoor airborne bacterial loads were not elevated above those measured immediately outdoors. The microbial assemblage of these indoor environments was considerably more diverse than reported in previous CAFO aerosol studies. Members of bacterial genera associated with animal gut microbiota, including Bacillus spp., Clostridium spp., and Lachnospira spp., were most frequently observed. We detected no recognized, acute respiratory pathogens, but identified the common opportunistic pathogen Aerococcus viridans in several samples. Fungal species were not recovered in any of the indoor clone libraries. Specific PCR assay for porcine circovirus demonstrated that this pathogen is prevalent in the atmosphere of swine environments sampled, but was not detected in the bovine dairy facilities.