Phenotypic and molecular characterization of antimicrobial resistant Escherichia coli from urinary tract infections in Port-Harcourt, Nigeria

Abstract

INTRODUCTION: Multidrug resistance among Escherichia coli causing Urinary Tract Infections (UTIs) is a major public health problem, threatening the effective treatment of UTIs infections. This study investigated the phenotypic and molecular characteristics of E. coli associated with UTIs in Port-Harcourt, Nigeria. METHODS: twenty-five non-duplicate isolates of E. coli from UTIs patients at University of Port-Harcourt Teaching Hospital, Nigeria were identified using Matrix assisted laser desorption ionization Time of flight (MALDI-TOF) Mass Spectrometry. The antimicrobial susceptibility patterns were determined using Kirby-Bauer disc diffusion technique. Phenotypic expression of ESBLs and AmpC beta-lactamase were determined using standard laboratory methods and PCR was used to detect ESBLs, AmpC, Quinolones and Aminoglycosides resistance genes. RESULTS: the isolates exhibited high rates of resistance to co-trimoxazole (76%), nalidixic acid (68%), ciprofloxacin (60%), gentamicin (44%) and low resistance to cefotaxime (20%) but were fully susceptible to cefoperazone/sulbactam, amikacin, nitrofurantoin, colistin and carbapenems. Phenotypic expression of ESBLs was recorded in 6(24%) isolates while genotypic detection revealed the highest prevalence of blaTEM 22(88%), followed by blaCTX-M-15 16(64%) blaSHV 7(28%) blaOXA-1 6(24%) while AmpC (blaCMY-2) gene was detected in 8(32%) isolates. Amongst the quinolone resistant isolates, qnr variants (qnrB, qnrD and qnrS) and aac(6')-Ib genes were detected in 7(28%) and 3(12%) isolates respectively while all gentamicin resistant isolates possessed the aacC2 gene. The co-expression of blaCTX-M-15 with quinolones and aminoglycoside genes were 20% and 40% respectively. The prevalence of multiple drug resistance was 52%.