phylogenetic groups, extended-spectrum b-lactamases and metallo-?-lactamase in escherichia coli isolated from fecal samples of patients with diarrhea in iran

aim : the aims of this study were to determine the phylogenetic groups and investigate phenotypic and genotypic of esbl and mbl-producing e . coli isolates from patients with diar­rhea in kerman, southeast of iran. background : escherichia coli is detected as a significant cause of sporadic and outbreaks of diarrhea. the emergence of extended-spectrum ?-lactamases (esbls) and metallo-?-lactamases (mbls)-producing escherichia coli caused problems in antibiotic treatments. e. coli strains can be assigned to four main phylogenetic groups, a, b1, b2 and d. patients and methods : two hundred sixteen e. coli isolates were obtained from diarrheal patients between june to december 2013. screening and confirmation tests of esbls and mbls were done by disk-diffusion and broth micro-dilution methods according to clsi 2013. the esbl-positive isolates were screened to determine the phylogenetic groups and presence of bla ctx-m-15 , bla oxa-1 , bla per-1 , bla vim and bla imp genes by pcr. results : in this study, from the 216 e. coli isolates 56 esbl-positive isolates were detected. among esbl-positive isolates, 51 isolates were positive for bla ctx-m-15 and one isolate were positive for both bla ctx-m-15 and bla oxa-1 genes. none of isolates were positive for bla per-1 , bla vim and bla imp genes. pcr assays for phylotyping of diarrhea isolates indicated that the isolates were belonged to group a (54.16%), b1 (11.11%), b2 (12.96%) and d (21.75%). esbl-positive isolates mostly distributed in phylo-groups a and d. the isolates possessed bla ctx-m-15 gene were belonged to a (35 isolates), b1 (5), b2 (3) and d (8) phylo-groups. according to the antimicrobial susceptibility results, imipenem was found to be the most active agent, while resistance to cefotaxime was high. conclusion : our results indicate that bla ctx-m-15 gene is widespread among diarrhea. esbl-producing e . coli isolates were dissemination among diversity of phylo-groups. the adequate infection control measures are essential to prevent further dissemination of ?-lactamases and mbls in our country.