The sequences of enterohemorrhagic Escherichia coli and Yersinia pestis that are homologous to the enteroaggregative E. coli heat-stable enterotoxin gene: cross-species transfer in evolution.

The enteroaggregative Escherichia coli heat-stable enterotoxin 1 (EAST1) gene is widely distributed among diarrheagenic E. coli. In this study, we examined the sequences of enterohemorrhagic E. coli (EHEC) strains by PCR and sequencing. All the EHEC strains possessed the EAST1 gene homologues but with two types of mutations. One of the mutation types was strongly associated with the large outbreak episodes in 1996 in Japan. Sequence comparison showed that the EHEC sequences are a branch of the EAST1 gene sequence family that showed the cross-species transfer in evolution among E. coli and Yersinia pestis.