Multiple Antimicrobial Resistance of Extended Spectrum Beta-Lactamase-Producing Escherichia coli from Small-Scaled Poultry Farms and Retail Chicken

Antibiotics used for agricultural purpose has contributed to the increased prevalence of antibiotic-resistant bacteria. The goal of this study was to investigate the prevalence and antimicrobial resistance of ESBL-producing E. coli in small-scaled poultry farms and retail chicken. The cultured E. coli isolates were subjected to phenotypic tests, susceptibility tests, and the polymerase chain reaction for detection of blaCTX-M, blaSHV, and blaTEM genes. From 120 samples each of chicken feces, retail chicken, soil and chicken feed, ESBL-producing E. coli isolates were detected in 75.9%, 63.6%, 39.2%, and 13.3% of the samples, respectively. Minimum inhibitory concentration (MICs) values indicated that ESBL-producing E. coli were resistance to ampicillin (MIC ≥ 32 μg/mL), gentamicin (MIC ≥ 16 μg/mL), cefotaxime (MIC ≥ 4 μg/mL) and ceftriaxone (MIC ≥ 4 μg/mL), respectively. The total resistance for imipenem was also observed at 1.0% (MIC ≥ 4 μg/mL) and none of the isolates were resistant to ceftazidime (MIC ≥ 16 μg/mL). ESBL-producing E. coli from chicken feces and retail chicken carried blaSHV gene at a rate of 6.8% and 5.7%, respectively and blaCTX-M gene was also revealed at 2.9% in retail chicken. Moreover, ESBL-producing E. coli isolated from soil harbored blaSHV and blaCTX-M genes at 5%. None of the feed samples yielded ESBLs genes. Twenty three resistance patterns were observed for multi-resistant ESBL-producing E. coli. This study highlights the prevalence of multi-antimicrobial resistant ESBL-producing E. coli in small-scaledpoultry farms and retail chicken, hence the need to review poultry management practices to minimize the occurrence.