Role of the flagellar basal-body protein, FlgC, in the binding of Salmonella enterica serovar Enteritidis to host cells.

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. Transposon mutagenesis identified flgC as a potential binding mutant of SE. Therefore, we hypothesize FlgC which plays a significant role in the binding ability of SE to the intestinal mucosa of poultry. To test our hypothesis, we created a mutant of SE in which flgC was deleted. We then tested the in vitro and in vivo binding ability of ∆flgC when compared to the wild-type SE strain. Our data showed a significant decrease in the binding ability of ∆flgC to intestinal epithelial cells as well as in the small intestine and cecum of poultry. Furthermore, the decrease in binding correlated to a defect in invasion as shown by a cell culture model using intestinal epithelial cells and bacterial recovery from the livers and spleens of chickens. Overall, these studies indicate FlgC is a major factor in the binding ability of Salmonella to the intestinal mucosa of poultry.