Gastroenterology and Hepatology from Bed to Bench

Abstract

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_VIMand 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_VIMand 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.