The potential for community exposures to pathogens from an urban dairy

The objectives of the study described in this article were to evaluate the variation and transport of fungal and bacterial concentrations in the air of a northern Mexico dairy cattle confined animal feeding operation (CAFO) and to determine the concentration and incidence of antibiotic-resistant Staphylococcus aureus isolates. Two-stage viable cascade impactors were used to measure the culturable airborne fungal organisms and bacteria. S. aureus resistant to penicillin, ampicillin, or cefaclor was identified. Samples were collected at three locations that were designated as on site, upwind of the cattle, and downwind of the cattle. The highest concentrations of culturable bacterial bioaerosols were consistently recovered from the on-site location. More than half of the organisms were antibiotic resistant at the on-site location. Elevated levels of culturable bacterial bioaerosols were recovered from the upwind site that may have been associated with the surrounding community. Bioaerosol concentrations were found in higher amounts than in a facility in the southwestern U.S. examined in the authors' previous study. The urban setting of the CAFO resulted in a higher potential for immediate community exposures.