Antibiotic Resistance Trends in Recurrent Paediatric Urinary Tract Infections: A Five-Year Single-Centre Experience

Background: Recurrent urinary tract infections (rUTIs) in children are increasingly complicated by antimicrobial resistance, leading to limited treatment options and challenging prophylactic management. Continuous local monitoring of resistance trends is essential for evidence-based stewardship. Methods: This retrospective study analysed recurrent paediatric UTI recorded between 2020 and 2024 at a tertiary hospital in Romania. Data were extracted using the ICD-10 code N39.0 and included demographic, clinical, and microbiological variables. Antimicrobial susceptibility testing followed CLSI standards. Associations between multidrug resistance (MDR) and clinical factors were assessed with χ² tests and Cramer's V, and predictors of MDR were evaluated by multivariable logistic regression. Temporal trends in resistance were examined using logistic regression with year as a continuous variable, and results were validated with the non-parametric Cochran-Armitage linear-by-linear χ² trend test to strengthen analytical rigour. Proportions are presented with Wilson 95% confidence intervals (CIs). Results: A total of 134 children met inclusion criteria for rUTI, of whom 130 had complete demographic and microbiological data and were included in analyses. Each episode represented a distinct culture-confirmed infection occurring ≥30 days apart. MDR occurred in 48.5% of isolates (95% CI, 40.2-56.9) and ESBL in 20.9% (95% CI, 14.9-28.5). MDR was significantly associated with urinary tract malformations (χ² = 5.78, p = 0.016) and continuous antibiotic prophylaxis (χ² = 4.23, p = 0.040). Neither logistic nor Cochran-Armitage trend analyses demonstrated a significant temporal increase in MDR (OR per year = 0.94; 95% CI 0.75-1.17; p = 0.566; χ² = 0.89; p = 0.346). Conclusions: MDR and ESBL rates among children with recurrent UTIs remain high but stable. The combined use of parametric and non-parametric trend analyses confirmed the absence of a significant upward trajectory, underscoring the need for ongoing surveillance and stewardship to maintain antibiotic effectiveness in paediatric care.