Positive stone culture is associated with a higher rate of sepsis after endourological procedures

The purpose of this study was to determine if there is a correlation between urine and/or stone cultures with postoperative sepsis in patients treated for renal and ureteral calculi. Three hundred and twenty-eight consecutive patients who underwent percutaneous nephrolithotomy (PCNL) or ureteroscopy from 2006 to 2009 were identified, all of whom had a stone culture obtained during surgery. All had a preoperative urine culture. Two hundred and seventy-four underwent ureteroscopy and 54 PCNL. All patients had either negative preoperative urine cultures or were given preoperative antibiotics for 1-7 days prior to surgery. Stone fragments were obtained during the procedure and sent for analysis. The primary endpoint was sepsis. Of 328 patients, 3 % (11/328) developed postoperative sepsis. 73 % (8/11) had positive stone cultures, while none had a positive preoperative urine culture. 8 % (8/96) with positive stone cultures and 1 % (3/232) with negative stone cultures developed sepsis (p = 0.003). The stone culture grew the same pathogen as the urine culture obtained on readmission in 64 % (7/11) of the patients, while 9 % (1/11) of preoperative urine cultures correlated with the readmission pathogen (p = 0.02). The pathogen causing infection had a significantly higher correlation with the organism grown on stone culture than the preoperative urine culture. The patients who developed sepsis did so despite preoperative antibiotics, and the pathogen grown on the preoperative urine culture was different from that seen post operatively. These results suggest that stone culture is more informative than preoperative urine culture for determining treatment of postoperative sepsis.