Stone culture retrieved during percutaneous nephrolithotomy: is it clinically relevant?

Stone culture has been frequently investigated following percutaneous nephrolithotomy (PNL) in the last decade. We aimed to crucially define the clinical role of stone culture in modifying the treatment plan in patients with postoperative sepsis. Between June 2012 and April 2013, a total of 79 consecutive PNL procedures were included. Perioperative data were prospectively maintained. Preoperative urine sample, retrieved stone fragments and postoperative nephrostomy tube urine sample were cultured and antibiotic sensitivity tests were performed. The occurrence of at least two of the systemic inflammatory response syndrome (SIRS) events during their inpatient stay was diagnostic of SIRS. The antibiotic regimen utilized and its modifications were reported. The preoperative culture was positive in 26 patients (32.9 %). The culture of stone fragments showed significant bacterial growth in 23 (29.1 %) cases. Significant growth on stone culture was significantly associated with the presence of preoperative urinary catheters and positive preoperative urine culture (P = 0.001, 0.006 respectively). Postoperative culture was positive in only six patients (7.6 %). SIRS was diagnosed in the first postoperative day in 12 patients (15.2 %). Leukocytosis was the only predictor of SIRS. Neither preoperative culture, stone culture nor postoperative culture was predictor of SIRS. Stone culture was positive in four patients with SIRS. Stone culture changed the treatment plan in only one patient. Our data do not support the routine implementation of stone culture in the PNL workup, as it did not indicate a change of antibiotic regimen in most of the cases.