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

ABSTRACT

The aims of this study were to investigate the phenotypic and genotypic of extended-spectrum beta-lactamase [ESBL] and metallo-beta-lactamases [MBLs] and determine phylogenetic background E. coli isolates from fecal samples of patients with diarrhea in Kerman, southeast of Iran 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. 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. 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. Our results indicate that bla[CTX-M-15] gene is widespread among diarrheagenic E. coli isolates. ESBLproducing 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