[Adherence patterns of Escherichia coli strains isolated from children with diarrhea]

Among enteropathogenic E. coli strains (EPEC) there are different patterns of adherence to the culture cells in vitro assay: localized, localized-like and diffuse. The adherence pattern is dependent on the ability of E. coli strains to cause of diarrhea. The strains locally adhering possess a 60 MDa plasmid--E. coli adherence factor (EAF), and produce characteristic histopathologic intestinal lesions linked with the presence of chromosomal eae gene. The pathogenicity of diffusely adherent as well as cells detaching E. coli (CDEC) remains controversial. The aim of the study was to identify the adherence patterns of E. coli strains isolated from children with diarrhea and to compare that patterns with the serotypes and the presence of EAF and/or pO157 plasmids, fimbriae and eae, stx1, and stx2 specific sequences. Nine out of examined E. coli strains showed the localized pattern of adherence. About half (46.8%) of strains were diffusely adherent and six isolates were cells detaching E. coli (CDEC). A total of 22 (23%) examined strains showed the presence of specific for verocytotoxins sequences. The results showed that many strains recognized on the ground of agglutination with specific EPEC antisera as unpathogenic could be an etiologic agents of diarrhea which are able to produce histopathologic lesions in the intestinal epithelium. In turn, many strains classified as EPEC could be unpathogenic on the basis of diffuse pattern of adherence.