Antimicrobial Resistance Profiles of Enterobacteriaceae Isolated from Poultry Farms in Zaria, Kaduna State

The overuse of antibiotics in commercial poultry farming is a recognized driver of antimicrobial resistance in zoonotic and commensal Enterobacteriaceae with potential for transmission to humans along the food chain. This study profiled the antimicrobial resistance of Enterobacteriaceae isolated from poultry cloacal swabs and litter samples collected from ten commercial poultry farms in Zaria, Kaduna State, North West Nigeria. A total of 180 Enterobacteriaceae isolates were recovered and subjected to disk diffusion susceptibility testing against 13 antibiotics including tetracyclines, beta-lactams, fluoroquinolones, and aminoglycosides. PCR was used to detect tetracycline resistance genes (tetA, tetB) and plasmid-mediated quinolone resistance genes (qnrA, qnrB) in selected isolates. Results showed that all ten farms had isolates with MDR profiles, with resistance to tetracycline (91%), ampicillin (88%), and co-trimoxazole (74%) being most prevalent. Fluoroquinolone resistance was detected in 37 percent of isolates. ESBL-producing Klebsiella pneumoniae was confirmed from 8 farms. tetA and qnrA genes were detected in 69 and 23 percent of resistant isolates, respectively. These findings indicate that Zaria poultry farms represent a significant environmental reservoir of transferable antibiotic resistance determinants. The study recommends the enforcement of veterinary antimicrobial prescription policies and routine AMR monitoring in poultry production systems. Keywords: Enterobacteriaceae, poultry, antimicrobial resistance, ESBL, Zaria.