Predictors of Multidrug-Resistant Urinary Tract Infections in Women: A Large Retrospective Cohort Study in a Romanian University Hospital.

Urinary tract infections (UTIs) represent a major cause of morbidity among adult women, with a disproportionate burden among postmenopausal patients. Limited data exist from Eastern Europe regarding pathogen distribution, antimicrobial resistance, and treatment patterns in hospitalized women. We conducted a retrospective cohort study of 948 adult female patients hospitalized with symptomatic UTIs between January 2021 and December 2023 in a Romanian multidisciplinary hospital. Demographic, clinical, and microbiological parameters were analyzed. Pathogen identification was performed by MALDI-TOF MS, and antimicrobial susceptibility testing followed EUCAST 2024 standards. Empiric treatment strategies and subsequent therapy modifications were assessed. Postmenopausal women accounted for 78.4% of cases and exhibited higher rates of recurrent UTIs, frailty, diabetes, urinary catheterization, and prior antibiotic exposure. Escherichia coli remained the predominant pathogen (52.6%), followed by Klebsiella spp. (18.4%) and Enterococcus spp. (12.1%). ESBL-producing organisms were found in 21.4% of E. coli and 38.7% of Klebsiella isolates. Pathogen distribution differed by age: younger women had a higher proportion of E. coli, whereas postmenopausal women showed a relative increase in opportunistic/healthcare-associated pathogens, particularly Klebsiella spp. and Enterococcus spp., consistent with higher catheter exposure and comorbidity burden. Carbapenem resistance was rare but present in a small subset of Klebsiella isolates with phenotypes compatible with OXA-48-like carbapenemase production. Empiric therapy most frequently included ceftriaxone or fluoroquinolones, but 27.8% of regimens required adjustment after susceptibility results. Independent predictors of prolonged hospitalization included age > 65 years, recurrent UTI, MDR infection, urinary catheterization, and delayed targeted therapy. UTIs among hospitalized adult women-especially postmenopausal patients-are strongly influenced by comorbidity burden and antimicrobial resistance. Local resistance patterns highlight the need for evidence-based empiric treatment and rapid therapy optimization. Strengthening stewardship and preventive interventions in elderly women is essential.