An outbreak of gastrointestinal illness with clinical and epidemiologic features of enterotoxigenic Escherichia coli (ETEC) occurred among patrons of a restaurant during April 1991. Illnesses among several groups of patrons were characterized by diarrhea (100%) and cramps (79%-88%) lasting a median of 3-5 days. Median incubation periods ranged from 50 to 56 h. A nonmotile strain of E. coli (E. coli O39), which was negative for heat-labile (LT) and heat-stable (STa, STb) ETEC toxins, was isolated only from ill patrons. This organism produced enteroaggregative E. coli heat-stable enterotoxin 1 and contained the enteropathogenic E. coli gene locus for enterocyte effacement; it did not display mannose-resistant adherence, but produced attaching and effacing lesions in the absence of mannose on cultured HEp-2 cells. E. coli that are not part of highly characterized but narrowly defined groups may be important causes of foodborne illness.
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Received 14 April 1997; revised 24 July 1997. The opinions and assertions contained herein are the private ones of the authors and are not to be construed as official or reflecting the views of the Departments of Defense or the Navy. Financial support: US Naval Medical Research and Development Command, Work Unit 62787 A.001.01.E1X.1521. Reprints or correspondence: Dr. Craig W. Hedberg, Acute Disease Epidemiology Section, Minnesota Department of Health, 717 Delaware St. S.E., P.O. Box 9441, Minneapolis, MN 55440-9441. * Members are listed after the text.