ENTERIC ESCHERICHIA-COLI INFECTIONS

Versatile pathogenic mechanisms, define at least six categories of Escherichia coli that cause diarrheal illnesses worldwide. Recent advances have uncovered new potential structure-function relationships among the toxins of enterotoxigenic E. coli, which cause secretory diarrhea. The Shiga-like toxins of enterohemorrhagic E. coli, associated with the hemolytic uremic syndrome, mediate bloody diarrhea not only in food and waterborne outbreaks, but also in daycare centers. Volunteer studies now convincingly demonstrate the Virulence of enteropathogenic E. coli and the critical role of its eae genetic determinant. Enteroaggregative E. coli, often associated with persistent diarrhea, primarily ly cause disease in infants, possibly, in part, by a guanylin-like enterotoxin. Several investigations suggest a possible pathogenic role for diffusely adhering E. coli, particularly in older children. Recent advances in polymerase chain reaction technology promise to further enlighten our understanding of the epidemiology of enteroinvasive E. coli, a significant cause of bacillary dysentery. This review highlights recent investigations that expand our understanding of diarrheagenic E. coli.