detection of enterohemorrhagic escherichia coli related genes in e. coli strains belonging to b2 phylogroup isolated from urinary tract infections in combination with antimicrobial resistance phenotypes

Background: this study was conducted to detect the prevalence of ehec virulence genes and antimicrobial resistance profile of escherichia coli strains belonging to b2 phylogroup implicated in urinary tract infections in semnan, iran. methods: from 240 urine samples 160 e. coli strains were isolated, biochemically. then, e. coli isolates were examined by multiplex-pcr for phylogenetic typing and detection of virulence genes (hly, stx1, stx2, eae) associated with enterohemorrhagic e. coli. finally, antimicrobial resistance of e. coli isolates were characterized using disk diffusion method. results: from 160 e. coli isolates, 75 strains (47%) were assigned to b2 phylogenetic group and prevalence of virulence genes were as follow: hly (21.3%), stx1 (16%), stx2 (10.6%) and eae (6.7%), subsequently. phenotypic antimicrobial resistance of b2 isolates showed that all isolates were sensitive to meropenem and furazolidone and then highest frequency of resistance was observed to streptomycin, oxytetracycline, neomycin, nalidixic acid and ampicillin (98.7% to 49.3%). also low resistance prevalence was observed in case of ceftizoxime, lincospectin, imipenem, chloramphenicol and flurefenicole (16% to 1.3%). conclusion: the data suggest a high prevalence of antibiotic resistance in upec strains belonging to b2 phylogroup even for the antimicrobials using in pet and farm animals and their potential to cause ehec specific clinical symptoms which may represent a serious health risk since these strains can be transmitted to gi tract and act as a reservoir for other uropathogenic e. coli and commensal strains.