Characterization of Enteropathogenic Escherichia coli Associated with Diarrhea Among Iranian Infants

Diarrhea is a cause of concern due to high morbidity and mortality in children. Enteropathogenic E. coli (EPEC) strains contribute to outbreaks of infantile diarrhea, especially in developing countries. This study was performed to investigate the contribution of EPEC as a cause of infectious diarrhea among Iranian infants. A total of 140 E. coli isolates from children with diarrhea and 110 from children without diarrhea were evaluated for the presence of EPEC. The E. coli isolates were examined for uidA, eae, and stx genes by polymerase chain reaction (PCR). The eae positive isolates were tested for the bfpA gene to differentiate typical and atypical EPEC. The EPEC isolates were typed by random amplified polymorphic DNA (RAPD-PCR). The E. coli isolates were confirmed by the presence of the uidA gene. The EPEC was diagnosed in 6 cases (4.2%) with diarrhea, which were positive for the eae gene, compared with negative results in the asymptomatic group. The bfpA were positive in 5 isolates (3.6%) that were categorized as tEPEC and 1 (0.09%) as aEPEC. All isolates showed genetically different patterns in RAPD-PCR. This study suggests that EPEC strains are important contributors to diarrhea in Iranian children. Because of the weakness of routine microbiological tests and poor specifity of serological tests, it is recommended that the EPEC strains are better detected by molecular methods.