Etiology of acute infectious diarrhea in a highly industrialized area of Switzerland.

During an 18-mo period between 1981 and 1982, a prospective study was conducted in 119 adult patients with acute diarrhea. A diarrhea-inducing microorganism or toxin could be identified in 38.7% of the patients. Salmonella sp and Campylobacter jejuni were the leading agents that caused diarrheal illness in 25% of the investigated population. Clostridium difficile was found in 6%, mainly after previous antibiotic therapy. Rotavirus was rarely isolated and enterotoxigenic Escherichia coli were not found. Clinical features in patients in whom an invasive agent was isolated did not differ from those in patients in whom no enteropathogens were found, although the occurrence of fecal leukocytes and positive hemoccult tests in the former group was significantly more frequent. More than 30% of the patients with negative stool cultures, however, showed fecal leukocytes and positive occult blood, which is suggestive of the existence of one or more invasive agent(s) so far unknown or not recognized.