Prevalence, Virulence Characterization, AMR Pattern and Genetic Relatedness of Isolates From Retail Seafood of Kerala, India.

, a halophilic bacterium often found in the marine or estuarine environment is a well-known enteropathogen responsible for foodborne outbreaks associated with seafood. The pathogenic strains of are marked by the presence of thermostable direct hemoylsin () and/or TDH related hemolysin () genes. This study aimed to investigate the prevalence and characteristics of potentially pathogenic in selected retail markets of Cochin, Kerala, along the south-western coast of the Indian subcontinent. One hundred samples collected from 10 retail markets were analyzed for the presence of pathogenic isolates of . Out of the 721 presumptive isolates, 648 were confirmed to be by gene amplification, among which 29 were Kanagawa phenomenon (KP) positive. Among these potentially pathogenic isolates, 17 possessed the gene whereas none of them had the gene. The faint amplification bands produced during the amplification of gene from two isolates was confirmed by sequencing. Multiplex O serotyping identified O1 serotype as the most prevalent serotype among the 29 potentially pathogenic isolates. Further, studies on the pandemic nature of these isolates revealed that 14 of the 29 were positive for the PGS-PCR, whereas all the isolates were negative for GS-PCR and HU-α PCR. The antibiogram of the isolates revealed that three isolates had significant Multiple Antibiotic Resistance (MAR) index of 0.2 or above. Pathogenic isolates resistant to second, third and fourth generation Cephalosporins were found to be present in the seafood studied. The molecular fingerprinting studies using ERIC-PCR, and PFGE revealed that three of these isolates shared close genetic similarities with the clinical strains. The environmental and seafood isolates that produced faint amplification bands during the amplification of gene suggests that the gene often goes undetected in environmental isolates. The conventional methods used to identify the pathogenic would be good for clinical isolates, but a more elaborate method is recommended for the detection of gene in environmental isolates. This is the first comprehensive study on pathogenic in Kerala, India and demonstrates for the first time, the isolation of potentially pathogenic , carrying gene from seafood collected from retail markets in Kerala.