Extended spectrum beta-lactamase producing Escherichia coli encoding aminoglycoside and fluoroquinolone resistant genes in urinary tract infection patients in a tertiary hospital in Nigeria

Abstract

Escherichia coli causing urinary tract infections (UTIs) remains the most common bacterial infection diagnosed among outpatients as well as hospitalized patients. This study aimed to detect the extended-spectrum beta-lactamase-producing E. coli habouring aminoglycosides and fluoroquinolone-resistant genes in UTI patients. A total of 372 clean-catch midstream urine samples of patients with UTI attending Alex Ekwueme Federal University Teaching Hospital Abakaliki, Nigeria (AE-FUTHA) was collected. The collected urine samples were processed using standard microbiology and molecular methods to isolate and identify E. coli. Detection of ESBL-producing E. coli was performed using the double-disk synergy test. The ESBL-producing E. coli were subjected to antimicrobial susceptibility testing following the standard Kirby–Bauer disk diffusion method. PCR-specific primers were used to screen for the ESBL, aminoglycosides and fluoroquinolone-resistant genes. Out of the 372 urine samples collected, 84 (22.58%) distinct E. coli isolates were recovered, out of which 24 (28.57%) were ESBL positive. While all the isolates were resistant to amoxicillin/clavulanic acid 24 (100%), others were highly resistant to aztreonam and sulfamethoxazole/trimethoprim 22 (91.7%), ceftriaxone 21 (87.5%), ceftazidime and cefotaxime 16 (66.7%). Resistance to a fluoroquinolone, a ciprofloxacin was observed in 15 (62.5%). Out of the 24 ESBL-positive isolates, 12 were selected based on their resistance to both aminoglycosides and fluoroquinolones antibiotics used. These ESBL-producing E. coli encoded blaOXA-1 3 (25%), blaSHV 3 (25%) and blaTEM 8 (66.7%). Fluoroquinolone genes, qnrA and qnrC were detected in all the isolates 12 (100%), while qnrB was detected in 10 (83.35). Aminoglycoside gene, ant (4′)-la was detected in all the isolates 12 (100%), while aph (2”)-ld was haboured by 10 (83.3%). Co-resistance of ESBL, fluoroquinolone and aminoglycoside (blaTEM + qnrA + qnrB + qnrC + ant (4′)-la + aph (2”)-lb) was observed in 8(66.7%). E. coli is one of the predominant bacteria isolated from UTI patients in Abakaliki. A high proportion have the ability to produce ESBL and predominantly encoded blaTEM with co-existence of fluoroquinolone gene, qnr and aminoglycoside, ant (4′)-la.