Detection of Shiga Toxin-Producing Strains of Escherichia coli (O157:H7) isolated from specimens of urinary and stool by Multiplex-PCR method

Background: Infection of shiga toxin-producing Strains of Escherichia coli has some other dangerous and deadly effects such as hemolytic uremic syndrome (HUS) in addition to diarrhea. Its diagnosis is difficult and there is no information on It's incidence in Iran. The goal of this study is to evaluate and detect shiga toxinproducing strains of E. coli isolated from urinary and stool specimens by multiplex- PCR method. Materials and Methods: One hundred samples out of 500 collected samples were screened. The selected samples have more chance of heaving different kinds of O157. After DNA extraction from the isolated strains, the multiplex PCR reaction for both stx1 and stx2 genes performed and consequently amplicons were examined by agarose gel electrophoresis. Samples were analyzed after painting by ethidium bromide. Findings: Only 3 cases (3%) of the studied sample were positive for the presence of STEC. All three cases were related to stx2. Two of them were related from feces samples and one of them was isolated from the urine samples. Conclusion: Although it seems that the incidence and prevalence of gastrointestinal infections by STEC are low in Iran, But because of the serious complications of the STEC infection such as HUS and HC and failure of detection of these strains by routine methods it is necessary to use molecular and serological diagnostic methods, especially in childhood clinics for recognizing doubtful cases.