The role of stone culture in patients undergoing mini-PCNL for kidney stone disease. Results from a large single-center series

Purpose To assess the impact of positive stone culture (SC) on infectious complications following mini-percutaneous nephrolithotripsy (PCNL) for kidney stones. Methods A retrospective analysis was conducted on 458 patients who underwent mini-PCNL (Amplatz sheath: 17.5 Ch) in a single center (February 2020-December 2024). Preoperative positive mid-stream urine culture (MUSC) was treated as per sensitivity. Patients were classified according to SC results as negative (Group 1: 383 patients) and positive (Group 2: 75 patients). Results Groups 1 and 2 had similar baseline characteristics, except for median age (63.7 vs. 55.7 years), proportion of females (45.2% vs. 70.7%%), proportion of patients with indwelling ureteral stent (12.3% vs. 33.3%), and proportion of positive MSUC (7.6% vs. 40%). Surgical time was similar in the 2 Groups and there was no significant difference in infectious complications (5.3% vs. 9.4%, p = 0.32), but patients in Group 2 had longer median hospital stays (4 vs. 3 days). Concordance of pathogens between MSUC and SC occurred in 30.8% (8/26) of cases. Postoperative bloodstream cultures were found positive in 3/12 patients, with pathogen concordance between SC and bloodstream culture in 2 patients. Multivariable regression analysis identified diabetes (OR 2.44), female gender (OR 3.08), and indwelling preoperative stent (OR 4.22) as significant predictors of positive SC. Conclusion Mini-PCNL showed a low rate of infectious complications with no difference between patients having positive or negative SC. SC can be useful to guide postoperative antibiotic therapy considering low rate of pathogen concordance between MSUC and SC.