Background and Aim: Enteroinvasive Escherichia coli (EIEC) strains include a group of diarrheagenic Escherichia coli (DEC) and are known to cause shigellosis-like symptoms in both adults and children. They belong to a limited number of serotypes and their somatic (O) antigens are identical with, or related to, certain Shigella antigens. EIEC strains are confirmed by demonstration of invasiveness by polymerase chain reaction (PCR) for detection of the ipaH (invasive plasmid antigen H)  gene that is specific for these strains among DEC.Since in our country,Iran study for detection of  these strains. hasnot been carried out therefore the aim of this study was detection of EIEC in diarrheal under 5 year old children in Tehran.

Materials and Methods: During the descriptive study,300stool samples were collected from children with diarrhea in Ali Asghar Hospital and children medicinal center of Tehran during 4 months (April-Jul 2008). E.coli species were isolated by standard bacteriological and biochemical tests. Presence of invasive plasmid antigen H (ipaH) gene in confirmed colonies was investigated by PCR technique.

Results: Among 300 stool specimens studied using culture method and biochemical tests,39(13%) E.coli species were isolated. Among these 39 strains,7(2.3%) strains containing ipaH gene (EIEC) were detected by PCR technique.

Conclusions: Enteroinvasive Escherichia coli (EIEC) in our country, Iran, may be as bacterial pathogen causing childhood diarrhea. Therefore we should apply new techniques for investigation of these strains.