Presence of colonization factor antigens on fresh isolates of fecal Escherichia coli: a prospective study.

In Dhaka, Bangladesh, fresh isolates of Escherichia coli from 197 patients with diarrhea were investigated for production of enterotoxin and possession of colonization factor antigen (CFA) I or II. Enterotoxigenic E. coli (ETEC) was isolated from 34% of the patients, and of the 67 enterotoxin-positive strains, 75% carried CFAs. Among 68 healthy control persons no strains positive for both enterotoxin and CFA were found. The CFAs in general were restricted to certain serotypes of E. coli. In a subgroup of patients, part of an ongoing surveillance study, mixed infection was seen in 23% of those from whom recognized pathogens were identified. There was a tendency to more severe dehydration when the two virulence factors, enterotoxin and CFA, were simultaneously present.