Escherichia coli O157:H7 as the predominant pathogen associated with the hemolytic uremic syndrome: a prospective study in the Pacific Northwest.

During a 12-month period, 14 patients with the hemolytic uremic syndrome were identified in a prospective study of enteric pathogens associated with this disorder. Of the 12 patients with a diarrheal illness preceding the onset of hemolytic uremic syndrome, fecal Escherichia coli O157:H7 was detected in seven (58%), all of whom had bloody diarrhea. Half of the siblings of these patients had concurrent nonbloody diarrhea. No source for infection with this organism was identified. Enteric infection with E coli O157:H7 occurs in the majority of cases of hemolytic uremic syndrome following diarrheal illness in the Pacific Northwest and may represent a previously overlooked cause of hemolytic uremic syndrome in other locales. Evaluation of all cases of hemolytic uremic syndrome for enteric pathogens should routinely include cultures for E coli O157:H7 until results of additional studies clarify the distribution of agents associated with hemolytic uremic syndrome in different geographic regions. These findings may provide new opportunities for the design of therapeutic and preventive strategies in this disorder.