Characterization of Escherichia coli strains from cases of childhood diarrhea in provincial southwestern Nigeria

In a study carried out in small-town and rural primary health care centers in southwestern Nigeria, 330 Escherichia coli strains isolated from 187 chi ldren with diarrhea and 144 apparently healthy controls were examined for v irulence traits, Based on the results of colony blot hybridization, strains were categorized as enteropathogenic E. coli (1.8%), enterotoxigenic E, co li (2.4%), enteroinvasive E, coli (1.2%), enterohemorrhagic E, coli (0.6%), enteroaggregative E, coli (10.3%), diffusely adherent E, coli (7.9%), cell -detaching E. coli (6.9%), and cytolethal distending toxin-producing E, col i (0.9%). E, coli strains that hybridized with a Shiga toxin gene probe but lacked other characteristics usually present in enterohemorrhagic E, coli constituted 8.4% of the isolates. Ninety-seven E, coli isolates adhered to HEp-2 cells in an aggregative fashion but did not hybridize with any of the probes employed in the study. Overall the pathotypes, apart from cytoletha l distending toxin-producing E. coli, were recovered both from children wit h diarrhea and from children without diarrhea, though to a lower extent fro m the healthy children, All diarrheagenic E. coli strains were associated w ith diarrhea (P < 0.02). Heat-stable-enterotoxin-producing enterotoxigenic E, coli showed significant association with diarrhea (P < 0.02), as did str ains that demonstrated aggregative adherence to HEp-2 cells (P < 0.04), but not those that hybridized,vith the CVD432 enteroaggregative probe.