High Prevalence of Multiple Antibiotic-Resistant, Extended-Spectrum β-Lactamase (ESBL)-Producing Escherichia coli in Fresh Seafood Sold in Retail Markets of Mumbai, India

In this study, fresh seafood in retail markets was investigated for the antibiotic susceptibility patterns of the faecal indicator Escherichia coli and distribution of important beta-lactamase encoding genes. E. coli were isolated from 50 (37 fish and 13 shellfish) fresh seafood samples and studied with respect to the phenotypic and genotypic characters of antibiotic resistance. Of 475 E. coli isolates from fresh seafood, 71.58% exhibited extended-spectrum beta-lactamase (ESBL)-positive phenotypes. A high percentage of isolates were resistant to indicator cephalosporins cefotaxime (95%), cefpodoxime (90.88%) and ceftazidime (90.29%). Relatively higher susceptibilities were recorded against imipenem (74.41%), cefoxitin (66.76%) and meropenem (51.18%). The multiple antibiotic resistance (MAR) index of 97.35% of the isolates was above 0.18. The ESBL genes bla(CTX-M), bla(SHV) and bla(TEM) were detected in 62.37%, 23.35% and 2.6% of E. coli isolates, respectively. The ESBL-producing isolates also harboured the metallo-beta-lactamase-encoding genes bla(OXA) (7.06%), bla(NDM) (4.42%) and bla(VIM) (0.88%). This study highlights the risk of dissemination of multidrug resistant E. coli in seafood consumer communities and also the need to improve the hygiene of the coastal waters, landing centres and the retail markets.