Urinary tract infection (UTI) is the most common complication following ureterorenoscopy in patients with urolithiasis, especially those with a positive preoperative urinalysis. However, it is unknown whether a positive preoperative urinalysis is still a risk factor for postoperative UTI when the preoperative UTI is adequately treated with antibiotics. This study aims to elucidate the risk factors for postoperative UTI in patients with urolithiasis complicated by a positive but treated preoperative urinalysis and to investigate whether the causative microbial agents differ between postoperative and preoperative UTI.

In this single-center study, 297 patients treated for urolithiasis with concomitant positive preoperative urinalysis between April 2021 and October 2023 were retrospectively identified. All these patients were adequately treated with antibiotics preoperatively, as indicated by negative cultures and absence of leukocyturia, before undergoing flexible ureterorenoscopy. Univariable and multivariable binary logistic regression analysis was performed to identify independent risk factors for postoperative UTI.

The mean age of this cohort is 59 years and 67% are male. A total of 71 (23.91%) patients developed postoperative UTI despite adequate preoperative UTI treatment. Multivariable adjusted logistic regression analysis showed that diabetes (OR=2.42, P=0.004) and stent duration > 2 months (OR=4.21, P<0.001) were independent risk factors for postoperative UTI, while preoperatively adequately treated UTI (OR=1.32, P=0.32) was not associated with postoperative UTI. Microbial culture results indicated that the same pathogen was observed in only 9.7% of cases.

A low concordance rate of microbial pathogens between preoperative and postoperative UTI, combined with multivariable-adjusted logistic regression results, showed that cured preoperative UTI did not increase the risk of postoperative UTI after flexible ureterorenoscopy. In addition, physicians may need to adjust antibiotic therapy for postoperative UTI based on culture results.