Phylogrouping and antimicrobial resistance analysis of extraintestinal pathogenic Escherichia coli isolated from poultry species

This study was undertaken to determine the prevalence and antimicrobial resistance pattern of extraintestinal pathogenic Escherichia coli (ExPEC) in the feces of healthy poultry and retail chicken. All 146 E. coli recovered from 351 samples were screened by PCR for detection of ExPEC strains. Nineteen (13.01%) isolates were confirmed as ExPEC. Distribution of ExPEC strains was revealed as follows: broiler (25%), layer (15.87%), and raw chicken (3.12%). Turkey, duck, and water samples were negative for ExPEC strains. ExPEC strains belonged to phylogenetic groups B2 (52.63%), A (36.84%), and D (10.53%). Twenty-three (15.75%) isolates were ESBL-positive, including four ExPEC strains. ESBL-positive E. coli were isolated from all the samples except turkey. A high degree of resistance to commonly used antimicrobials, namely nalidixic acid (95.89%), tetracycline (95.89%), trimethoprim (89.04%), colistin (82.88%), and ciprofloxacin (54.11%), including s-lactam antimicrobials ampicillin (84.93%) and amoxicillin/clavulanic acid (81.51%), was expressed by the isolates. Out of fifteen randomly selected ESBL-positive E. coli isolates, s-lactam genes, namely blaTEM, blaCTX-M, and blaOXA, were detected in three, six, and one, respectively. Poultry and raw chicken harbor multidrug-resistant, ESBL-type E. coli as well as ExPEC and these strains may be transmitted to humans via the food chain.