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Abstract
Enterococci may be reservoirs of antibiotic resistance, and it is important to characterize the strains isolated from animals and their environments. This study analyzed enterococci from four poultry houses for six growouts on a farm. Two houses on the farm were control houses and did not use any antimicrobials while two other houses on each farm used flavomycin, virginiamycin, and bacitracin during different poultry growouts. Litter, chick boxliners, feed, and poultry carcasses were obtained from each house and cultured for the presence of enterococci. Enterococci species were identified using a species-specific multiplex-PCR. Vitek, a commercial culture typing system, was also used a confirmatory procedure. Additionally, Enterococcus faecium isolates were further characterized using BOX-PCR and Pulsed- Field Gel Electrophoresis (PFGE). Enterococcus faecalis (n=763; 52%) and E. faecium (n=578; 40%), were isolated most often from the farm and houses regardless of antimicrobial treatment. Enterococcus faecium analyzed by BOX-PCR and PFGE appeared to be genetically different as few clusters were observed.