Antimicrobial resistant profiles of Escherichia coli and contaminated Salmonella spp. from pork and butcher shops

Abstract

Antimicrobial resistant profiles of Escherichia coli isolated from pork and environment samples of six retail butcher shops in Bangkok, Thailand, were studied. Of the total samples, 73.3% were positive for Salmonella spp. and 86.7% were positive for E. coli. E. coli were tested for the minimum inhibitory concentrations against 12 antimicrobial agents that are commonly prescribed for infection in humans. The resistances to quinolones comprising of moxifloxacin and ciprofloxacin were 15.4% and 11.5%, respectively. The β-lactams resistance was observed at less frequent rates at 9.6% for cefotaxime, 3.8% for amoxicillin/ clavulanic acid, 3.8% for cefoxitin, and 1.9% for ceftazidime, but all isolates were sensitive to cefoperazone/sulbactam and cefpirome. Furthermore, 11.5% of the isolates produced ESBL enzymes. Aminoglycosides resistance was observed for gentamycin at 17.3% while amikacin resistance (0%) was not found. Trimethoprim/sulfamethoxazole showed the highest resistance at 57.7%. Only one colistin resistant isolate (MIC at 8 µg/ml) was found, but it did not carry the plasmid mediated colistin resistance genes mcr-1 and mcr-2. Amplifying the gene integrase 1 (intI1), 3.9% of the isolates yielded positive PCRs. In this study, the antimicrobial resistant rates of E. coli from pork and markets were relatively low and mcr genes were not yet distributed in the tested E. coli.