Prevalence of Listeria Monocytogenes in Freshwater Fish of Northeast India and Their Molecular Characterization by PCR

Abstract

Five different species of freshwater fish (total number sampled =1,165) were collected from
various fish markets of northeast India and screened for the presence of Listeria
monocytogenes using enrichment and selective plating methods. Polymerase Chain Reaction
(PCR) methods were standardized for confirmation of L. monocytogenes isolates and
detection of various virulence genes (hlyA, iap, plcA and plcB). Out of the total samples, 27
(2.31%) L. monocytogenes resistant to three different antibiotics could be isolated with a
prevalence rate of 5.45%, 3.67%, 1.43%, 1.38% and 0.33% in C. batrachus, H. fossilis, A.
testudinus, M. seenghala, and L. guntea, respectively. Virulent-associated genes; hlyA, iap,
plcA and plcB were detected in 40.7%, 29.6%, 40.7% and 22.2% of the 27 isolates,
respectively. The prevalence of antibiotic resistant L. monocytogenes harbouring virulence
genes in freshwater fish can contaminate other food and food products, thereby affecting
human and animals directly or indirectly.