Prevalence, molecular characterization, genetic heterogeneity and antimicrobial resistance of Listeria monocytogenes associated with fish and fishery environment in Kerala, India

Abstract

The prevalence of Listeria monocytogenes in the retail fish markets of the Kerala, India was investigated by screening 227 samples comprising of marine finfish ,shellfish, ready-to-cook fish products, ready-to-eat fish products, dried fish and retail ice. The prevalence of L. monocytogenes and L. innocua was 2.7 per cent and 17.2 per cent respectively. Sample category wise, prevalence of L. monocytogenes was higher in marine finfish (1.8 per cent ) and retail ice (0.9 per cent ). All the L. monocytogenes isolates carried virulent genes namely inlA, inlC, inlJ, hlyA, iap, plcA, prfA genes and majority belonged to 1/2a, 3a serogroups. L. monocytogenes isolates were multidrug-resistant and showed resistance to ampicillin, penicillin, erythromycin, tetracycline and clindamycin. Enterobacterial repetitive intergenic consensus-polymerase chain reaction delineated 58 per cent genetic heterogeneity among the L. monocytogenes strains. The study reports that genetic similarities of the isolates were interlinked to their serogroup and sample origin.