Quinolone Resistance and Virulence Genes Prevalence of Uropathogenic Escherichia coli Isolated from Kidney Transplant Recipients with Urinary Tract Infections in Tehran, Iran

Background: Kidney transplantation is the last suggested treatment option for patients with end-stage kidney disease. Uropathogenic Escherichia coli (UPEC) is a leading cause of urinary tract infections (UTIs) in transplant recipients. The rising resistance rates to therapeutic antibiotics and the presence of various virulence factors in E. coli pose serious concerns for this vulnerable population. This study aimed to investigate quinolone resistance and key virulence genes in UPEC isolates from kidney transplant recipients. Materials and methods: Fifty E. coli isolates were collected from kidney transplant recipients diagnosed with UTIs who were referred to Yekta, Gholhak, and Labbafi Nezhad Hospital laboratories in Tehran, Iran, from 2022 to 2024. Antimicrobial susceptibility testing (AST) was performed using the Kirby–Bauer disc diffusion method. Additionally, polymerase chain reaction (PCR) was conducted to detect the presence of ompT, fimH, hlyA, aac (6’)-Ib, qnrA , and qnrB genes. Results: The resistance rates for the following antibiotics were as follows: ampicillin (94%), amoxicillin-clavulanate (54%), ampicillin-sulbactam (64%), piperacillin-tazobactam (54%), cefazolin (88%), cefepime (70%), cefotaxime (80%), cefoxitin (48%), cefpodoxime (80%), doripenem (16%), ertapenem (20%), meropenem (72%), imipenem (18%), gentamicin (34%), tobramycin (44%), amikacin (28%), ciprofloxacin (62%), trimethoprim/sulfamethoxazole (70%), nitrofurantoin (20%), and fosfomycin (86%). Additionally, the frequencies of quinolone-associated resistance genes were reported, with aac (6′)-Ib at 30%, qnrA at 18%, and qnrB at 8%. The distribution of virulence genes includes ompT at 40%, fimH at 82%, and hlyA at 10%. Discussion and conclusion: The rising resistance rates to ciprofloxacin, combined with the higher prevalence of a specific virulence gene in E. coli isolates from kidney transplant recipients with UTIs, underscore the need for phenotypic and molecular antimicrobial susceptibility testing. Additionally, analyzing virulence genes is crucial for developing effective treatment strategies and preventing E. coli infections in UTI patients. Keywords: Escherichia coli , multidrug resistance, kidney transplantation, urinary tract infections, Quinolon