Fimbrial adhesins of Salmonella typhimurium: Role in bacterial interactions with epithelial cells

S. typhimurium initiates infection of its mammalian host by attachment to mucosal surfaces in the intestine and subsequent invasion of epithelial cells. To date, three S. typhimurium fimbrial operons, fim, lpf and pef, have been characterized. This analysis suggests that fimbrial adhesins fulfill multiple functions during the initial phase of an infection. In addition to their role in colonization of the small intestine, adhesins contribute to the tissue tropism for Peyer's patches, which is characteristic for Salmonella infections. Furthermore, by mediating the initial contact to epithelial cells, fimbrial adhesins appear to be necessary for invasion and possibly for elicitation of an inflammatory response. Thus, fimbriae are important virulence factors of S. typhimurium and their future analysis promises to yield fascinating new insights into host-parasite interactions of this pathogen.