Designing multiplex PCR method to investigate three stx1, stx2 and eaeA genes in E.coli O157:H7 isolated from patients with clone cancer

Introduction: The most strains of Escherichia coli are harmless but Enterohemorrhagic E. coli (EHEC) serotype O157: H7 is a major intestinal pathogen, that causes intestinal disease such as hemorrhagic colitis, hemolytic uremic syndrome, and especially Acute kidney failure in children. This study was conducted to evaluate the presence of virulence genes eae A, stx2, stx1 in E. coli O157: H7 isolated from patients with colon cancer in Iranian population by multiplex-PCR assay. Method: In this study, participators were age range of 40–60 years. A total of 132 E. coli O157H7 derived from the fecal specimens of 426 patients with colorectal cancer under chemotherapy and 43 E. coli O157H7 isolates from fecal specimens of 632 healthy people. The isolates identification and confirmation was performed using conventional morphological and biochemical analysis. Total DNA of the isolates was extracted according to the extraction column kits protocol. Gene specific primers were designed using primer3 and gene runner software. Finally, Determination of the frequency of virulence genes eae A, stx2 and stx1 was performed using Multiplex-PCR.Result: The results were showed that the prevalence of eae A, stx2, and stx1 genes was 9.38%, 6.57% and 22.53% in patients respectively. And prevalence of these virulence genes in healthy people was determined 0.31%, 0.15% and 0.47%. In 69.4% of patients, these three genes were present together.Discussion: In present study, it seems that the frequency of virulence genes in cancer patients who are treated with chemotherapy increased. These could be responsible for high prevalence of infections in patients after treatment. Furthermore, significant role of E. coli in inflammatory bowel disease, and since the Shiga toxin producing E. coli lead to hemolytic uremic syndrome, the isolation of STEC is essential. In this field it is highly significant using fast and precise techniques such as the molecular methods.

کلیدواژه ها:

Escherichia coli ، virulence Factors ، eae A ، stx2 ، stx1