Phenotypic and Genotypic Characteristics of Uropathogenic Escherichia coli Isolates from Kenya

Abstract

Introduction: Uropathogenic Escherichia coli (UPECs) are a significant cause of urinary tract infections (UTIs). In Kenya, UTIs are typically treated with b-lactam antibiotics without antibiotic susceptibility testing, which could accelerate antibiotic resistance among UPEC strains. Aim: This study determined the occurrence of UPEC producing extended-spectrum b-lactamases (ESBLs), the genes conferring resistance to b-lactams, and the phylogenetic groups associated with ESBLs in Kenyan UPECs. Methodology: Ninety-five UPEC isolates from six Kenyan hospitals were tested for ESBL and plasmidmediated AmpC b-lactamase (pAmpC) production by combined disk diffusion and disk approximation tests, respectively. Real-time and conventional polymerase chain reactions (PCRs) were used to detect three ESBL and six pAmpC genes, respectively, and phylogenetic groups were assigned by a quadruplex PCR method. Results: Twenty-four percent UPEC isolates were ESBL producers with blaCTX-M (95.6%), blaTEM (95.6%), and blaSHV (21.7%) genes detected. Sixteen isolates had blaCTX-M/TEM, whereas five had blaTEM/CTX-M/SHV. A total of 5/23 ESBLs were cefoxitin resistant, but no AmpC genes were detected. The UPECs belonged predominantly to phylogenetic groups B2 (31/95; 32.6%) and D (30/95; 31.6%), while groups B2 and A had the most ESBL producers. Conclusions: b-Lactam antibiotics have reduced utility for treating UTIs as a quarter of UPECs were ESBL producing. Single or multiple ESBL genes were present in UPECs, belonging primarily to phylogenetic groups B2 and A.