Prevalence and antibiotic resistance patterns of bacterial agents isolated from urinary tract infections in outpatients referred to Kashan Reference Laboratory in Iran during 2021-2022

The prevalence and patterns of antibiotic resistance among bacterial agents causing urinary tract infections (UTIs) can vary over time and across different geographical regions. This study aimed to evaluate the prevalence and antibiotic resistance patterns of bacterial agents isolated from urine cultures of outpatients referred to the Reference Laboratory in Kashan, Iran, during 2021-2022.

This cross-sectional study analyzed 7365 urine culture samples collected from patients referred to the Reference Laboratory in Kashan, Iran, between April 2021 and March 2022. Urine samples were obtained using the mid-stream method under sterile conditions and cultured on MacConkey agar, blood agar, and specific bacterial media. The identified organisms were tested for antibiotic resistance using the disc diffusion method on Mueller Hinton agar medium following the guidelines of the National Committee for Clinical Laboratory Standards (CLSI 2020).

Among the 7365 patients with urine cultures, 401 individuals (5.4%) had positive culture results, with a predominance of women (88.8%). Escherichia coli (62.5%) and Klebsiella (24.6%) were the most frequently isolated organisms. Escherichia coli exhibited the highest resistance rates to cefazolin (54.7%), cotrimoxazole (51%), and ciprofloxacin (41%), while showing the lowest resistance to imipenem and nitrofurantoin (4.4%). Klebsiella showed the highest resistance to cefazolin (58.3%) and cotrimoxazole (41.4%), with the lowest resistance to imipenem (7.1%). Gram-positive bacteria demonstrated the highest resistance to clindamycin (71.4%) and cotrimoxazole (57.9%), while displaying the lowest resistance to gentamicin (14.7%) and nitrofurantoin (17.5%).

Escherichia coli and Klebsiella were the predominant causative agents of UTIs, exhibiting similar antibiotic resistance patterns. Empirical antibiotic treatment based on these results may be considered before obtaining culture results.