Virulence-Encoding Genes Conserved in Salmonella Isolated From Humans, Poultry, and Seafood.

Diverse virulence genes encode for the Type III secretion system (T3SS) in bacteria. In Salmonella, these genes are located in the Salmonella pathogenicity Islands 1 and 2 (SPI-1 and SPI-2), and they facilitate bacterial invasion and replication within macrophages, contributing to the burden of nontyphoidal Salmonella infections. In this study, we investigated the prevalence of selected virulence-encoding genes in 30 laboratory stocks of Salmonella enterica serovar Enteritidis from Nigeria (16 isolates) and nonclinical sources comprising poultry and seafood from India (14 isolates). Analysis of PCR amplicons revealed that the genes sseB, sseD, sseF, sseT, and invH were conserved in all the isolates except for two isolates obtained from clams, which did not have the sseD and sseF genes. In addition, the sseC and sseG genes were absent from all the tested isolates. This study provides insights into the distribution of selected T3SS genes among Salmonella spp. isolated from clinical and raw animal food sources in Nigeria and India, respectively.