Impact of preoperative urine culture on postoperative febrile urinary tract infection after ureterorenoscopic lithotripsy

INTRODUCTION: Ureterorenoscopic lithotripsy (URSL) has become the first-line treatment for upper urinary tract calculi smaller than 20 mm in Japan. However, postoperative febrile urinary tract infection (f-UTI) sometimes leads to fatal outcomes. Few studies have evaluated the impact of bacterial strains and counts from preoperative urine cultures on f-UTI risk. This study investigated these associations and discussed potential preventive strategies. MATERIALS AND METHODS: CFU/mL). F-UTI incidence was assessed according to demographics, bacterial strains, and counts. Statistical analyses included chi-square test, Student's t-test, and multivariate logistic regression. RESULTS: Postoperative f-UTI occurred in 127 cases (8.4%). Multivariate analysis identified preoperative f-UTI and positive urine culture as independent predictors. F-UTI incidence was 5.3% in culture-negative versus 12.1% in culture-positive cases. High-count cases showed a significantly higher f-UTI rate than low-count cases (17.9% vs. 11.2%, p < 0.01). Escherichia coli was associated with f-UTI even at low counts, while Enterococcus faecalis increased risk only at high counts. Multidrug-resistant strains such as Corynebacterium and Enterococcus faecium were also high-risk strains. DISCUSSION: Preoperative positive urine culture was an independent risk factor for f-UTI after URSL. Both bacterial strain and count influenced infection risk. When high-risk strains or high bacterial counts are present, careful antibiotic selection, shorter operative time, and intrarenal pressure control may help reduce postoperative f-UTI.