Escherichia coli Urinary Tract Infections from a Romanian Pediatric Hospital: Antimicrobial Resistance Trends, ESBL Prevalence, and Empirical Treatment Implications

Background: Urinary tract infections (UTIs) are among the most common bacterial infections in children, with Escherichia coli as the leading pathogen. The rise in antimicrobial resistance, particularly extended-spectrum β-lactamase (ESBL) production, complicates empirical therapy, especially in countries with limited surveillance like Romania. Methods: We conducted a retrospective study on 248 pediatric patients aged 0–17 years diagnosed with E. coli UTI and admitted to a children hospital from Bucharest, Romania, between 2022 and 2024. Data collected included clinical presentation, laboratory values, and antimicrobial susceptibility testing. Patients were divided into ESBL and non-ESBL groups, and statistical comparisons were performed using SPSS v25. Results: Infants accounted for 68.1% of cases, with male sex predominating in this group (85.3%). ESBL-producing strains were identified in 19% of patients, more frequently in males (25% vs. 13.6%, p = 0.024). While inflammatory markers (CRP, leukocytes, neutrophils) were higher in complicated infections, they were paradoxically lower in ESBL cases. Non-ESBL isolates were highly susceptible to fosfomycin, third-generation cephalosporins, nitrofurantoin, and gentamicin. ESBL isolates showed resistance to most β-lactams but retained high susceptibility to fosfomycin (100%), carbapenems (>89%), cefoxitin (89.4%), and amikacin (85.1%). Conclusions: Our findings support the use of fosfomycin, nitrofurantoin, and selected aminoglycosides as viable empirical options in pediatric UTIs. Given the substantial ESBL prevalence and resistance to commonly used oral agents, local antibiogram data should guide empirical treatment strategies to preserve antibiotic efficacy and combat resistance.