مقايسه تنوع ژني fimH در اشريشياكلي يوروپاتوژن و فلور روده

Comparing of fimH gene variation in normal flora and uropathogenic Escherichia coli

Aims: Since FimH protein has a main role in colonization of UPEC strains and causing infection, preparing the vaccine containing this adhesion is concerned. The aim of the study was to investigate the fimH gene variation among urinary and feces isolates.Materials & Methods: Urine and feces samples were taken from 15 patients affected by UTI, with the origin of Escherichia coli. After the culture of samples, Escherichia coli suspected colonies were separated and confirmed by biochemical tests. Urine and fecesʹ Escherichia coli isolates were cultured in LB Broth environment, and were incubated one night. Genomic DNA was extracted and fimH gene was amplified using PCR. The gene sequence analysis was carried out using MEGA4, ClustalW and CLC Bio software. Results: In the alignment of fimH gene sequence related to the urine isolates with fimH gene associated with UTI 89 strain several mutations were observed. Moreover, there was the sequence difference between pathogenic strains isolated from urine and non-pathogenic feces strains. fimH sequence of feces isolates in C-terminal had insignificant mutations. Conclusion: Despite the 100 percent similarity of fimH gene sequence in four urinary and feces isolates, the difference of sequence in FimH protein and gene causes pathogenic isolates to have more affinity to urothelial cells. Insignificant mutation in C-terminal leads to the formation of truncated FimH, which can affect the attachment of feces strains to urotheilial cell; however, attachment factor has no role in Uropathogenic Escherichia coli pathogenic by itself.