The long term goal is to develop and optimize management strategies that minimize the prevalence of zoonotic enteric bacteria, including those resistant to antimicrobial agents, in dairy production systems. The specific objective of this project is to conduct longitudinal sampling of dairy animals in Pennsylvania to evaluate the presence and prevalence of antimicrobial resistance in the enteric bacterial population.
APPROACH: <br/>Sampling will primarily be conducted on dairy farms (composite manure samples), but samples will also be collected at buying stations and slaughterhouses. Quarterly composite manure samples will be collected from 25 to 40 dairy operations. Samples will also be collected from culled dairy animals (or pens) at slaughterhouses and at facilities where animals are housed en route to the slaughterhouses (i.e. buying stations and auction houses). Samples will be cultured for the presence of E. coli and Salmonella and isolates will be tested for resistance to a panel of antibiotics.