Cellular routes of invasion by enteropathogens

The cellular pathways of infection utilized by pathogenic enteric bacteria have important implications for their clinical manifestations. Yersinia rea ches Peyer's patches via M cells and uses plasmid-encoded factors to resist phagocytic cells. Shigella also translocates via M cells and incapacitates phagocytes, but subsequently re-enters the epithelium basolaterally to eli cit an acute inflammatory response. Salmonella has recently been shown to b oth colonize Peyer's patches via M cells and independently disseminate to e xtraintestinal sites via CD18-expressing phagocytes. M cell-mediated entry can lead to gastroenteritis and mucosal antibody production, while systemic dissemination can result in septicemia and elicitation of systemic immune responses.