Phylotyping of bla<inf>CTX-M-15</inf> gene in extended spectrum beta lactamase producing Escherichia coli isolates from clinical samples in Iran

Abstract

© This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. Aim: Escherichia coli (E. coli) producing extended-spectrum β-lactamase (ESBL) has become prevalent in worldwide. The ESBLproducing E. coli is genetically various, and isolates have been divided into four phylog-groups (A, B1, B2 and D). Material and method: One hundred and fourteen (ESBL) producing E. coli isolates were isolated from urinary tract infections (58 isolates) and diarrhea (56 isolates) samples. Screening and confirmation tests of ESBLs were done by disk-diffusion and broth micro-dilution methods according to CLSI. The isolates were studied to determine the phylogenetic groups and presence of and beta-lactamase (bla CTX-M-15 ) gene. Results: Phylogenetic analysis revealed that ESBL producing UTI isolates belonged to four phylogenetic groups A (43.10%), B1 (3.44%), B2 (18.96%) and D (34.48%). PCR assays of ESBL producing diarrheic E. coli isolates indicated that 67.85% fell into A, 7.14% to B1, 10.71% to B2 and 14.28% to D phylogenetic groups. Forty one isolates from urine samples and 52 isolates from diarrheic samples were positive for the bla CTX-M-15 gene respectively. Phylotyping of isolates possessed β-lactamase gene indicate that the isolates distributed in four phylogenetic groups including A (52 isolates), B1 (5), B2 (12) and D (24) phylogenetic groups. Conclusion: Production of ESBL among E. coli strains isolated from UTI and diarrheic was relation to change in phylogenetic distribution toward non-B2 phylogenetic groups, in particular groups A and D. In addition, results of current study indicated the higher prevalence of bla CTX-M-15 gene in investigated isolates.