Sialic acid is required for nonspecific adherence of Salmonella enterica ssp enterica serovar Typhi on Caco-2 cells

To initiate infection, bacteria must adhere to and colonize host tissues. Specific and nonspecific mechanisms participate in the adherence process. Salmonella enterica ssp. enterica serovar Typhi (S. Typhi) must first adhere to the intestinal epithelium to invade and disseminate throughout the host. In this study, the role of colonic epithelial cell surface sialic acid in the adherence of S. Typhi was defined. Neuraminidase treatment of colonic Caco-2 cells removed 27-58% of surface sialic acid. Thus desialylation diminished the adherence of S. Typhi by 41%. Sialic acid treatment of S. Typhi had no effect on their adherence to neuraminidase-treated or control cells. These results indicate that sialic acid on the surface of colonic cells enhances S. Typhi adherence. These findings may suggest novel therapeutic strategies for S. Typhi infections.