Virulotyping of seafood associated Salmonella enterica subsp. enterica isolated from Southwest coast of India

Infections due to seafood associated Salmonella serovars are a great risk to public health. It is known that genes involved in pathogenesis of Salmonella spp. are clustered within Salmonella pathogenicity islands. Therefore, this study was aimed at detecting the prevalence of 12 different virulence associated genes coded by 4 pathogenicity islands, namely, SPI-1, SPI-2, SPI-3 and SPI-5, among 31 Salmonella enterica spp. isolated form the Southwest coast of India. Two sets of Hexaplex PCR were developed. Result showed that, hilA, invA, ssaB, ssaP, ssaQ, ssaT, sseD and mgtC were 100% prevalent in this study followed by rhuM (96.77%), sseC (93.5%) and sopB and pipC (90.34%). The detection limit of the optimized multiplex PCR was tested with lowest detectable concentration of 0.005 ng μl. This assay is a reproducible and sensitive assay for the detection of Salmonella by screening several virulence genes presence in SPI. Finding of presence or absence of virulence genes may explain the reason behind stringent host adaptation of seafood associated serovar of Salmonella.