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

We retrospectively analyzed 1514 URSL cases performed between October 2018 and September 2023. Positive urine culture was defined as ≥104 CFU/mL. Cases were divided into a low-count group (<106 CFU/mL) and a high-count group (≥106 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.