Airborne antibiotic resistant and nonresistant bacteria and fungi recovered from two swine herd confined animal feeding operations

Inhalation of microorganisms could be a health concern for workers inside and downwind of animal confinement units. Using the Andersen two-stage viable microbial particle sizing sampler, air samples were collected from locations upwind, inside, and downwind during two visits to two swine herd confined animal feeding operations. Six samples were taken at each location on each site. Bacteria isolated from each site were then tested for antibiotic resistance using the Kirby-Bauer disc diffusion method. Resistant bacterial forms were found inside and downwind of the swine confinement facilities, indicating that resistant organisms were being produced in and released from these facilities. Resistance to a battery of antibiotics including ampicillin, erythromycin, oxytetracycline, penicillin, tetracycline, and tylosin was found in the following bioaerosols: Staphylococcus aureus, Salmonella spp., and fecal coliforms. The major conclusion reached by this study was that bacteria were recovered inside and downwind of these facilities in levels that previous studies had stated could cause a potential human health hazard.