Changes in Antibiotic Resistance of Microorganisms Isolated from Urine Cultures Over the Years

Abstract

Background: Inappropriate use of antimicrobial drugs for the treatment of urinary tract infections can lead to antibiotic resistance. This study aimed to determine the distribution of UTI-causing bacteria isolated from urine samples sent to our laboratory and their resistance rates to various antimicrobials.

Materials and Methods: In this retrospective study, urine culture samples from patients aged 18 years and older, sent to the microbiology laboratory of a tertiary education and research hospital between January 2019 and July 2023, were examined. The distribution of pathogens detected in urine cultures, antibiotic resistance rates, and antibiotic resistance patterns of E. coli and Klebsiella species over the years were investigated.

Results: A total of 2676 urine culture samples, sent to our laboratory, were included in the study. Gram-negative pathogens were isolated in 1920 (71.7%) samples. The most frequently isolated pathogens were E. coli, Klebsiella spp., and Enterococcus species. Among E. coli isolates, the antibiotics with the lowest resistance rates were fosfomycin (4.3%), nitrofurantoin (4.8%), and amikacin (5.4%). Among Klebsiella spp. isolates, the lowest resistance rates were observed for imipenem (35.4%), fosfomycin (40.4%), and gentamicin (47.4%). From 2019 to 2023, an increasing resistance to trimethoprim/sulfamethoxazole, ertapenem, piperacillin-tazobactam, and ciprofloxacin was observed in both E. coli and Klebsiella spp. isolates.

Conclusions: For effective UTI treatment, accurate identification of pathogens, performing antibiotic susceptibility testing, and effective surveillance at both hospital and provincial levels are necessary.