Isolation and Characterization of Novel Antibiotic-Resistant Bacteria from Clinical Samples of Patients with Recurrent Urinary Tract Infections

Abstract

Background: Recurrent urinary tract infections (rUTIs) pose significant clinical challenges, particularly with the emergence of antibiotic-resistant bacterial strains. This study aimed to isolate and characterize novel antibiotic-resistant bacteria from clinical samples of patients with rUTIs.

Methods: A prospective cross-sectional study involved 150 patients with clinically diagnosed rUTIs. Urine samples were collected and processed using standard microbiological techniques. Bacterial isolation was performed using selective media, followed by identification through biochemical tests using API identification systems. Antibiotic susceptibility testing was conducted using the disk diffusion method and E-test strips according to CLSI guidelines. Resistance mechanisms were detected using standard phenotypic methods, including combination disk tests for ESBL detection and modified Hodge test for carbapenemase screening.

Results: A total of 187 bacterial isolates were obtained from 150 samples, with 89.3% showing multidrug resistance patterns. Escherichia coli was the predominant isolate (42.8%), followed by Klebsiella pneumoniae (18.7%) and Enterococcus faecalis (15.5%). Novel resistance patterns were identified in 23.5% of isolates, including extended-spectrum β-lactamase (ESBL) production in 67.4% of Enterobacteriaceae. Carbapenem resistance was detected in 12.3% of isolates, primarily in K. pneumoniae and Pseudomonas aeruginosa.

Conclusions: This study reveals alarming rates of multidrug resistance among bacterial isolates from rUTI patients, with emerging novel resistance patterns threatening current therapeutic options. These findings underscore the urgent need for antimicrobial stewardship programs and the development of alternative treatment strategies.