Molecular detection of lactose fermenting enteroinvasive Escherichia coli from patients with diarrhea in Tehran-Iran

Enteroinvasive Escherichia coli (EIEC) is one the cause of acute diarrhea and bacillary dysentery in developing countries. Routine diagnostic microbiology tests are not capable to distinguish EIEC from other pathogenic or non-pathogenic E. coli. PCR, targeting ipaH, virF, virB and other virulence genes, is a diagnostic method for detecting E. coli pathotypes. Using PCR, we identified EIEC by PCR targeting ipaH and virF genes among E.coli isolates from patients with diarrhea at the selected hospitals in Tehran. Isolates of E. coli were cultured from 140 specimens of patients with diarrhea using culture and IMViC test. DNA was extracted using commercial kits and and tested for uidA, ipaH and virF genes by PCR. Totally, 140 E. coli isolates were confirmed by IMViC tests and PCR targeting uidA gene. Of 140 E. coli isolates, 5 (3.6%) were positive for the ipaH gene, 4 (2.9%) contained virF gene and 4 (2.9%) were positive for both ipaH and virF genes. These results indicated that EIEC is a considerable acute diarrheagenic pathogen in adults and infants. More- over, virF gene is suggested for evaluation of invasiveness of EIEC.