Enterotoxin-producing Escherichia coli and diarrheal disease in adult travelers: a prospective study.

Twenty-eight United States adult travelers to developing countries participated in a prospective study designed to determine whether there was an association between diarrheal illness and, the acquisition of strains of enteropathogenic Escherichia coli. Stool specimens were collected and stored in transport media before, during, and after travel and at the onset of any diarrheal illness. From each specimen, five E. coli colonies were screened for enterotoxin production with the suckling mouse test, and three E. coli colonies were tested for penetration of epithelial cells (Sereny test). Positive colonies were serotyped. Eleven of 28 travelers experienced diarrheal illness. Of these, four (36%) acquired enterotoxin-producing E. coli at the time of illness. None of the 17 well travelers had identifiable enterotoxinproducing E. coli before, during, or after travel. No strains of E. coli that penetrated epithelial cells were found. Three of the four travelers with enterotoxinproducing E. coli acquired serotype 027:K:H2O, a serotype not previously recorded at the Center for Disease Control. This study suggests that enterotoxinproducing E. coli, as detected by the suckling mouse test, may be a significant cause of traveler's diarrhea in adults.