<i>Vibrio cholerae</i> Outbreak in Italy

To the Editor: Enteroaggregative Escherichia coli (EAggEC) heat-stable enterotoxin 1 (EAST1) was originally found as an enterotoxin of EaggEC (1). Recently, Yamamoto et al. (2) reported that the EAST1 gene, or its variants, were present not only in EAggEC but in other diarrheagenic E. coli, including some enteropathogenic E. coli (EPEC) and enterotoxigenic E. coli (ETEC). Hedberg et al. (3) found that an outbreak of gastrointestinal illness in 1991 had been caused by EAST1-producing E. coli that possessed the EPEC gene locus for enterocyte effacement. We propose that E. coli producing EAST1 but possessing no other identifiable pathogenic properties may compose either a new group of diarrhea-associated E. coli or a new subgroup of ETEC.