Carbapenemases and Extended-Spectrum β-Lactamase–Producing Multidrug-Resistant Escherichia coliIsolated from Retail Chicken in Peshawar: First Report from Pakistan

We report the prevalence of extended-spectrum β-lactamases and carbapenemases in Escherichia coliisolated from retail chicken in Peshawar, Pakistan. One hundred E. coliisolates were recovered from retail chicken. Antibiotic susceptibility testing was carried out against ampicillin, chloramphenicol, kanamycin, nalidixic acid, cephalothin, gentamicin, sulfamethoxazole-trimethoprim, and streptomycin. Phenotypic detection of β-lactamase production was analyzed through double disc synergy test using the antibiotics amoxicillin-clavulanate, cefotaxime, ceftazidime, cefepime, and aztreonam. Fifty multidrug-resistant isolates were screened for detection of sul1, aadA, cmlA, int, blaTEM, blaSHV, blaCTX-M, blaOXA-10, blaVIM, blaIMP, and blaNDM-1genes. Resistance to ampicillin, nalidixic acid, kanamycin, streptomycin, cephalothin, sulfamethoxazole-trimethoprim, gentamicin, cefotaxime, ceftazidime, aztreonam, cefepime, amoxicillin-clavulanate, and chloramphenicol was 92, 91, 84, 73, 70, 67, 53, 48, 40, 39, 37, 36, and 23% respectively. Prevalence of sul1, aadA, cmlA, int, blaTEM, blaCTX-M, blaIMP, and blaNDM-1was 78% (n =39), 76% (n =38), 20% (n =10), 90% (n =45), 74% (n =37), 94% (n =47), 22% (n =11), and 4% (n =2), respectively. blaSHV, blaOXA-10, and blaVIMwere not detected. The coexistence of multiple antibiotic resistance genes in multidrug-resistant strains of E. coliis alarming. Hence, robust surveillance strategies should be developed with a focus on controlling the spread of antibiotic resistance genes via the food chain.