Enteroadherent Escherichia coli exhibiting localized pattern of adherence among infants with diarrhoea in Brazil--incidence and prevalence of serotypes

Abstract

The incidence of enteroadherent Escheridhia coli exhibiting localized adherence to HeLa cells was investigated using the EAF probe (Nataro et al., J. Infect. Dis., 152:560-563, 1985) among 126 infants below 3 years of age along with 126 age-matched healthy controls in Brazil. The EAF probe proved to be sensitive and specific in detection of enteroadherent E. coli. EAF-probe positive E. coli was isolated from 23.0% of the infants with acute diarrhoea while the corresponding rate of isolation from healthy controls was 11.9%. EAF-probe positive E. coli strains belonging to the classical enteropathogenic E. coli (EPEC) serogroups were more often associated with diarrheal cases (18.3%) than with strains isolated from control healthy infants (5.6%). The predominant EAF-probe positive E. coli serotypes were O55:H-, O111:H2 and O119:H6. These serotypes, especially O111:H2, were mainly isolated from cases with diarrhoea suggesting a strong causal association. Among the EAF positive non-EPEC serotypes, the most prevalent serotype was O88:H25 and this represents a, hitherto, unrecognized diarrheagenic E. coli serotype.