Renal Pelvis Urine Sampling in Patients with Obstructed, Infected Ureterolithiasis: A Retrospective Quality Improvement Initiative.

Purpose: Patients who present with urinary tract infections secondary to obstructing stones occasionally fail to improve on treatment based on midstream urine culture (MUSCx). Varying microbiomes between the bladder and the renal pelvis may account for this. In this study, we sought to investigate the utility of obtaining a renal pelvis urine culture (RPUCx) at the time of stenting to guide antibiotic treatment prior to definitive stone operation. Materials and Methods: RPUCx was obtained in 257 patients presenting with obstructive ureteral stones undergoing emergent stenting. Concordance rates of RPUCx to MUSCx and blood cultures were examined. Operative time and infectious complication rates after definitive stone management between the two groups were studied. A comparison of those who received an intraoperative RPUCx with those who did not was carried out. Results and Conclusions: RPUCx was obtained in patients undergoing emergent stenting from 2018 to -2021; 31% (52/168) of patients had pathogens in the renal pelvis that were absent in the MUSCx. RPUCx had a greater concordance rate with blood culture results compared with MUSCx (95% vs 50%). Drawing RPUCx intraoperatively did not significantly change operative time (15.9 vs 13.6 minutes, p = 0.15). Treatment tailored to RPUCx resulted in lower rates of post-stone management complications (odds ratio 0.26, 95% confidence interval = 0.08-0.83; p = 0.01). RPUCx at the time of stenting can guide treatment and decrease post-treatment complications without additional operative time, confirming utility in the treatment of patients with infection secondary to obstructing stones.