Characteristics of Bacteria in Urine and Stones from Patients Treated with Percutaneous Nephrolithotomy and Association with Postoperative Infection

Min Lei,1,2,&ast; Zheng Jiang,1,2,&ast; Peng Xu,1,2 Zhenglin Chang,1– 3 Yuyan Zhang,4 Shike Zhang,1,2 Lingyue An,1,2,5 Shujue Li,2,3 Tao Zeng,2,3 Hans-Göran Tiselius,6 Yuhao Zhou,1,2 Guohua Zeng,2,3 Wenqi Wu1,2 1Department of Urology, The Second Affiliated Hospital, Guangzhou Medical University, Guangzhou, Guangdong, 510260, People’s Republic of China; 2Guangdong Key Laboratory of Urology, Guangzhou Medical University, Guangzhou, Guangdong, 510260, People’s Republic of China; 3Department of Urology, The First Affiliated Hospital, Guangzhou Medical University, Guangzhou, Guangdong, 510260, People’s Republic of China; 4Guangzhou Institute of Dermatology, Guangzhou, Guangdong, 510095, People’s Republic of China; 5Department of Urology, Guizhou Provincial People’s Hospital, Guiyang, Guizhou, 550002, People’s Republic of China; 6Department of Clinical Science, Intervention and Technology (CLINTEC), Karolinska Institute, Stockholm, 14186, Sweden&ast;These authors contributed equally to this workCorrespondence: Wenqi Wu; Guohua Zeng, Email 2009681012@gzhmu.edu.cn; gzgyzgh@vip.sina.comBackground: The purpose of this study was to identify bacterial differences between urine cultures (UC) and stone cultures (SC) in patients with complex kidney stones and to determine any correlation with post-percutaneous nephrolithotomy Systemic Inflammatory Response Syndrome (SIRS).Methods: Perioperative data of 1055 patients with complex kidney stones treated with first-stage Percutaneous Nephrolithotomy (PCNL) from September 2016 until September 2021 were included. Preoperative mid-stream urine samples and surgically obtained stone material were subjected to bacterial culture and antibiotic sensitivity tests. Preoperatively, antibiotic usage was determined by the UC or local bacterial resistance patterns. After PCNL treatment, antibiotic selection was guided by stone bacterial culture result and clinical symptoms. The effect of different preoperative antibiotic regimens based on urine cultures and postoperative antibiotic treatment based on stone cultures were assessed.Results: Positive stone cultures (SC+) were significantly more common than positive urine cultures (UC+) (31.9% vs 20.9%, p < 0.05). Escherichia coli (E. coli) was the most common uropathogen in both urine (54.3%) and stones (43.9%). The difference was statistically significant (p < 0.05). Moreover, UC+SC-, UC-SC+, UC+SC+, and preoperative serum creatinine were independent risk factors of postoperative SIRS. The incidence of SIRS in the UC+SC+ patients with different bacteria in stones and urine (51.6%) was higher than that in other culture groups. The antibiotic resistance of E. coli inside the stone was increased when prolonged preoperative antibiotics were administered to UC+ patients.Conclusion: The bacterial spectrum and positive outcome of culture in urine and stones were significantly different. The incidence of postoperative SIRS was highest in patients with UC+SC+ but with different bacteria strains. Prolonged pre-surgical antibiotic treatment apparently induced higher drug resistance for bacteria inside the stone.Keywords: kidney stones, bacterial spectrum, antibiotic resistance, stone culture, urine culture