Antibiotic Prophylaxis for Ureteroscopy With a Negative Pressure Suction Sheath

Inclusion Criteria: 1. Age 18-75 years. 2. Diagnosed by CT with renal and/or upper ureteral stones, with the longest stone diameter being ≤2cm. 3. Scheduled to undergo fURS lithotripsy. 4. No preoperative symptoms of infection such as chills and fever, and the most recent preoperative urine culture is negative. 5. No immunosuppressive status and no urinary flow obstruction caused by anatomical abnormalities. 6. No use of long-acting antimicrobial agents within 7 days prior to surgery, and no use of intermediate or short-acting antimicrobial agents within 72 hours prior to surgery. 7. Has signed and dated an informed consent form, indicating that the patient or their legal representative has been fully informed about the study-related information and has agreed to participate. Exclusion Criteria: 1. Pregnant or lactating women. 2. Allergy to the investigational drug(s). 3. Participation in other clinical trials within 30 days. 4. Presence of other active infection foci requiring antimicrobial treatment. 5. Concomitant severe systemic diseases, such as cardiac or pulmonary disease, malignant tumors, and immunodeficiency states. 6. Congenital malformations of the urinary tract. 7. History of kidney transplantation or urinary diversion surgery. 8. Unable to provide samples or complete follow-up according to the study protocol. 9. Unable to provide informed consent. 10. Inability to achieve complete placement of the flexible negative-pressure suction sheath. 11. Any other conditions that the investigator deems unsuitable for participation in this study. 12. History of diabetes mellitus, immunocompromised. 13. Renal insufficiency, neurogenic bladder. 14. Recent preoperative history of stone-related fever. 15. Long-term indwelling urinary drainage tube. 16. Urine white blood cells \>5/HPF (High Power Field) or positive for urine nitrites. 17. Large stone burden (e.g., staghorn calculus) or moderate to severe hydronephrosis. 18. Imaging findings showing turbid urine in the renal pelvis where pyonephrosis or infectious stones cannot be excluded.