Statement problem and Objective: One of the important complications in gastrointestinal infections or Escherichia Coli O157:H7 is bacterial hemorrhagic complications. Therefore, inhibiting bacterial binding is a suitable strategy for preventing infection using tir and intimin genes. In this regard, the present study investigates the effect of fecal microbiome on the expression of intimin and tir genes in E. coli O157:H7. Materials and Methods: Two standard and clinical samples were used. First, Escherichia Coli samples were confirmed using 16S rRNA primers and used to investigate the genes involved in tir binding and PCR. Then, standard and clinical Escherichia Coli bacteria were co-cultured with 10 bacterial suspensions obtained from the feces of 10 healthy individuals in LB medium. After the steps of RNA extraction and cDNA synthesis, gene expression was examined by the real-time PCR method. Results: The expression level of tir genes was significantly reduced after interaction with the intestinal microbiome obtained from the feces of healthy humans. Conclusion: The presence and interaction of other intestinal flora bacteria probably affect preventing the binding and pathogenicity of enterohaemorrhagic Escherichia Coli bacteria, thus it can be used for the prevention and treatment of gastrointestinal infections.

enterohaemorrhagic Escherichia Coli, tir binding genes