Phenotypic and Genotypic Characteristics of Uropathogenic <i>Escherichia coli</i> Isolates from Kenya

Abstract

<b><i>Introduction:</i></b> Uropathogenic <i>Escherichia coli</i> (UPECs) are a significant cause of urinary tract infections (UTIs). In Kenya, UTIs are typically treated with β-lactam antibiotics without antibiotic susceptibility testing, which could accelerate antibiotic resistance among UPEC strains. <b><i>Aim:</i></b> This study determined the occurrence of UPEC producing extended-spectrum β-lactamases (ESBLs), the genes conferring resistance to β-lactams, and the phylogenetic groups associated with ESBLs in Kenyan UPECs. <b><i>Methodology:</i></b> Ninety-five UPEC isolates from six Kenyan hospitals were tested for ESBL and plasmid-mediated AmpC β-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. <b><i>Results:</i></b> Twenty-four percent UPEC isolates were ESBL producers with <i>bla</i>_CTX-M (95.6%), <i>bla</i>_TEM (95.6%), and <i>bla</i>_SHV (21.7%) genes detected. Sixteen isolates had <i>bla</i>_CTX-M/TEM, whereas five had <i>bla</i>_{TEM/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. <b><i>Conclusions:</i></b> β-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.