Prevalence and Resistance Patterns of Uropathogens in Critically Ill Patients at a Tertiary Care Hospital in Tehran: Implications for Antimicrobial Stewardship in Developing Countries.

Background: Antimicrobial resistance is a critical global threat in resource-limited settings with underdeveloped laboratory capacity and stewardship programs. Intensive care unit (ICU) patients are at high risk for complicated urinary tract infections (cUTIs) caused by multidrug-resistant (MDR) uropathogens. Local resistance data are essential to guide empirical therapy and design effective stewardship interventions. Methods: We conducted a retrospective, cross-sectional study (March 2020-December 2022) of 127 adult ICU patients with cUTIs at a tertiary hospital in Tehran, Iran. Urine isolates were identified by standard phenotypic methods, and antimicrobial susceptibility testing (AST) was performed via disk diffusion following Clinical and Laboratory Standards Institute guidelines. Resistance phenotypes-extended-spectrum beta-lactamase (ESBL) production, carbapenem-resistant Enterobacteriaceae, vancomycin-resistant enterococci (VRE), difficult-to-treat Pseudomonas, and pan-drug-resistant (PDR) Acinetobacter baumannii-were defined using current breakpoints. Results: Escherichia coli (52.2%) and Klebsiella pneumoniae (26.9%) predominated. Among Enterobacterales, 60.4% produced ESBL and 30.2% were carbapenem resistant. VRE comprised all enterococcal isolates; PDR A. baumannii occurred in one case. No significant associations were found between resistance profiles and sepsis, septic shock, or mortality. Multivariable analysis identified heart failure (odds ratio [OR] 2.45; 95% confidence interval [CI] 1.15-5.21; p = 0.017) and longer ICU stay (OR 1.03 per day; 95% CI 1.01-1.05; p = 0.012) as independent predictors of MDR infection. Conclusions: We report an alarming burden of MDR uropathogens in Tehran ICUs, underscoring the need for tailored empirical-therapy guidelines, enhanced antimicrobial stewardship programs, and multicenter surveillance to curb resistance and improve patient outcomes.