Enterotoxigenic Escherichia coli: Identification and characterization

Strains of enterotoxigenic E. coli (ETEC), only recently recognized, are assuming a major role in our understanding of diarrheal diseases, particularly in the developing world. They are now known to be: one of the common causes of childhood diarrheas, usually of mild to moderate severity, in the developing world; a common cause of the cholera syndrome in native adults living in cholera-endemic areas; the most common identifiable cause of the diarrhea of travelers from developed countries who visit the developing world; an occasional cause of nursery outbreaks of diarrhea in developed countries; and an occasional cause of common source outbreaks of diarrhea secondary to fecal contamination of water and food. As these organisms are being isolated with increasing frequency from many laboratories in diverse geographic areas, there sometimes arises confusion about their identification and characterization. An attempt is made here to put in perspective our present understanding of these organisms, how they are isolated and characterized, and how they are related both to strains of E. coli that cause diarrhea by other mechanisms and to other enterotoxigenic organisms.