Phylogenetic groups, extended-spectrum β-lactamases and metallo-β-lactamase in Escherichia coli isolated from fecal samples of patients with diarrhea in Iran

AIM: The aims of this study were to investigate the phenotypic and genotypic of extended-spectrum β-lactamase (ESBL) and metallo-β-lactamases (MBLs) and determine phylogenetic background E. coli isolates from fecal samples of patients with diarrhea in Kerman, southeast of Iran BACKGROUND: The emergence of ESBLs and MBLs-producing E. coli caused problems in antibiotic treatments. E. coli strains can be assigned to four main phylog-groups, including: A, B1, B2 and D. PATIENTS AND METHODS: E. coli isolates (n=216) were obtained from fecal samples of patients with diarrhea between June and December 2013. ESBLs and MBLs were confirmed by disk-diffusion and broth micro-dilution methods. Using PCR, the ESBL-positive isolates were screened to determine the phylo-groups and the presence of bla(CTX-M-15), bla(OXA-1), bla(PER-1), bla(VIM) and bla(IMP) genes. RESULTS: ESBL-positive isolates (n= 56) were detected. Among ESBL-positive isolates, 51 isolates were positive for bla(CTX-M15) and one isolate was positive for both bla(CTX-M-15) and bla(OXA-1 )genes. None of the isolates were positive for bla(PER-1), bla(VIM) and bla(IMP) genes. PCR assay for phylotyping of isolates indicated that the isolates were belonged to groups A (54.16%), B1 (11.11%), B2 (12.96%) and D (21.75%). The isolates possessed bla(CTX-M-15) gene were belonged to A (35 isolates), B1 (5), B2 (3) and D (8) phylo-groups. CONCLUSION: Our results indicate that bla(CTX-M-15) gene is widespread among diarrheagenic E. coli isolates. ESBL-producing E. coli isolates were disseminated among a diversity of phylo-groups. Further studies are necessary to identify the ESBL genes in relation to phylogenetic groups.