Urine versus stent cultures and clinical UTIs

Current American Urological Association guidelines recommend pre-operative antimicrobial therapy based on prior urine cultures (UC); however, the role of stent culture (SC) in urologic practice is unclear. We examined whether UC and SC differed at the time of stent removal, as well as the association, microbiology, and timing of subsequent UTIs as related to SC.

This was a retrospective review of 159 patients with ureteral stents for indications of urolithiasis, benign stricture, malignant obstruction, and kidney transplant. UC and SC were analyzed at the time of stent removal. Patients were followed for 12 months after stent removal for development, concordance, and timing of clinical UTIs.

In 159 patients, 15% had positive UC and 45% had positive SC. Of patients who had positive SC, 66% had negative UC. All patients with positive UC had identical micro-organisms on SC; however, 33% of these had SC with additional micro-organisms. Relative to those with both negative UC and SC, patients with negative UC and positive SC had a 5.7 odds, and those with both positive UC and SC had a 13.6 odds of developing a clinical UTI within 12 months. Concordance of SC and future UTI was highest in those with post-operative sepsis, and those with Candida species on SC.

SC was a unique risk factor for development of UTI within 12 months of stent removal. Clinicians should consider SC results when empirically treating those with post-operative sepsis or those with UTI after Candida on SC.