Escherichia coli as a cause of diarrhea

Escherichia coli is the best-known member of the normal microbiota of the human intestine and a versatile gastrointestinal pathogen. The varieties of E. coli that cause diarrhea are classified into named pathotypes, including enterotoxigenic, enteroinvasive, enteropathogenic and enterohemorrhagic E. coli. Individual strains of each pathotype possess a distinct set of virulence-associated characteristics that determine the clinical, pathological and epidemiological features of the diseases they cause. In the present brief review, we summarize the key distinguishing features of the major pathotypes of diarrheagenic E. coli. Knowledge of the pathogenic mechanisms of these bacteria has led to the development of rational interventions for the treatment and prevention of E. coli-induced diarrhea. In addition, investigations into E. coli virulence are providing useful insights into the origins and evolution of bacterial pathogens more generally. (C) 2002 Blackwell Publishing Asia Pty Ltd.