Pathogenesis of<i>Escherichia coli</i>Diarrhea

Abstract

Two Escherichia coli strains isolated in Vietnam from American soldiers with diarrhea and acute "colitis" were examined for virulence in both in vitro and in vivo experimental models. Their biologic properties were compared with those of an enterotoxin-producing Esch. coli strain implicated in disease of swine as well as with those of four other Esch. coli and a virulent shigella strain. The two Vietnam strains produced an enterotoxin in a rabbit ileal-loop model and in volunteers caused a diarrheal syndrome resembling that of cholera. Two nontoxigenic Esch. coli strains gave evidence of penetrating epithelial cells in laboratory models and caused a shigella-like illness in man characterized by dysentery, tenesmus, urgency, hyperpyrexia and hypotension with systemic toxemia. Thus, strains of Esch. coli can cause disease in man by at least two mechanisms: elaboration of a cholera-like enterotoxin; and shigella-like intestinal epithelial penetration.