Five-Year Cumulative Antibiogram of Urinary Isolates: Implications for Empirical Therapy and Antimicrobial Stewardship

Urinary tract infections (UTIs) are among the most common bacterial infections worldwide. Increasing antimicrobial resistance (AMR) poses a major challenge to empirical therapy. This study aimed to evaluate the five-year cumulative antibiogram of urinary isolates and assess resistance trends to guide empirical treatment strategies. A retrospective analysis was conducted on urinary isolates collected between 2021 and 2025. Only the first isolate per patient per year was included according to cumulative antibiogram principles. Antimicrobial susceptibility testing was performed using routine laboratory methods and interpreted according to EUCAST criteria. Resistance trends were evaluated descriptively. A total of 40,168 urinary isolates were analyzed. The most common pathogens were Escherichia coli, Klebsiella pneumoniae, and Enterococcus spp. E. coli demonstrated high susceptibility to nitrofurantoin (88–93%), fosfomycin (~95%), and carbapenems (~100%), while susceptibility to ciprofloxacin (~28–42%) and trimethoprim-sulfamethoxazole (~36–53%) was lower. Klebsiella pneumoniae showed lower susceptibility rates overall, particularly to beta-lactams and fluoroquinolones, with preserved activity of carbapenems (~70%). Non-fermentative pathogens such as Acinetobacter baumannii demonstrated extremely low susceptibility rates (<20% for many tested agents), highlighting limited antimicrobial treatment options. Increasing resistance to commonly used oral agents limits empirical treatment options. Nitrofurantoin and fosfomycin remain effective for E. coli, while carbapenems retain activity against resistant Gram-negative pathogens. Continuous local surveillance is essential to guide empirical therapy and antimicrobial stewardship strategies.