Characterization of SEN3800-associated virulence of <Emphasis Type="Italic">Salmonella enterica</Emphasis> serovar Enteritidis phage type 8

Salmonella is a major public health concern due to the consumption of contaminated food. Salmonella enterica serovar Enteritidis (SE) infection in humans is often associated with the consumption of contaminated poultry products. Binding of the bacterium to the intestinal mucosa is a major pathogenic mechanism of Salmonella in poultry. In this study, transposon mutagenesis identified SEN3800 as a potential binding mutant of SE. Therefore, we hypothesize that SEN3800 plays a role in the colonization ability of SE in the gastrointestinal tract of poultry. To test our hypothesis, we created a mutant of SE in which SEN3800 was deleted. We then tested the in-vitro and in-vivo binding ability of ?SEN3800 when compared to the wild-type and complemented SE strains. Our data showed a significant decrease in the binding ability of ?SEN3800 to T84 intestinal epithelial cells, as well as in the small intestine and cecum of poultry. Furthermore, this binding defect correlated to a defect in invasion, as evidenced by a cell culture model using T84 intestinal epithelial cells and bacterial recovery from the livers and spleens of chickens. Overall, these studies indicate that SEN3800 contributes to the colonization ability of Salmonella in the gastrointestinal tract of poultry.