Simultaneous detection of phylogroups and ESBL genes in E. coli using Multiplex PCR

Abstract

Background: Escherichia coli (E. coli) strains harbor various allelic versions of beta lactamase genes and their identification using conventional phenotypic tests is a tedious and time consuming task. In the present study, multiplex PCR is performed for the simulatanoues detection of E. coli phylogroups and extended-spectrum β-lactamase- (ESBL) genes.Methods: A total of 128 E. coli isolates from urine samples were screened for antibiotic resistance and expression of ESBL activity using phenotypic and genotypic methods. Uniplex and multiplex PCRs were used to detect E. coli phylogroup detrminants and blaCTX-M-15, blaOXA-1 and TEM1 genes. Chi Square test of independence was employed for evaluating significant levels at P value < 0.05. Results: Phylogroup B2 was detected as the predominant group (36%) followed by group D (30%), A (25%) and B1 (9%). The highest resistance was seen against nalidixic acid (100%) and the lowest against amoxicillin-clavulanic acid (55%). Significant P values were observed for resistance against cefotaxime and cefepime in the phylogroup B2 while resistance against cefoxitin, sulfamethoxazole and fosfomycin was significantly associated with group D. Combination disc diffusion test (CDDT) showed ESBL activity in 42% E. coli isolates. A significant association of blaCTX-M-15 gene was observed for phylogroup B2 (P = 0.007). Moreover, a combination genotype of blaCTX-M-15 and TEM1 was also found statistically prevalent in phylogroup B2 (P = 0.006).Conclusion: The study highlights the alarming rise in antibiotic resistance and delineates B2 a predominant phylogoup with a high prevalence of blaCTX-M-15 and TEM1 genes in urinary E. coli isolates.Keywords: UTI; E. Coli; Phylogenetic groups; ESBL genes; Multiplex PCR