Do you treat preoperative asymptomatic bacteriuria (ASB) with antibiotics?

Treatment of Preoperative Asymptomatic Bacteriuria

For most surgical procedures, you should NOT screen for or treat preoperative asymptomatic bacteriuria—the major exception is endoscopic urologic procedures that breach the mucosal lining, where screening and treatment are strongly recommended to prevent sepsis. 1

Procedure-Specific Recommendations

Endoscopic Urologic Procedures WITH Mucosal Trauma (TREAT)

Screen and treat ASB before these procedures: 1

• Transurethral resection of prostate (TURP)
• Transurethral resection of bladder tumor (TURBT)
• Ureteroscopy with lithotripsy
• Percutaneous stone surgery
• Any procedure breaching the urinary tract mucosal lining

Treatment protocol: 1

• Obtain preoperative urine culture for targeted therapy (not empiric)
• Administer short-course antibiotics: 1-2 doses only
• Initiate 30-60 minutes before the procedure
• Avoid prolonged courses (increases resistance and adverse effects without additional benefit)

Rationale: The risk of postoperative sepsis is substantial (13% in untreated patients vs 0-4.5% in treated patients in RCTs). 1 This represents a heavily contaminated surgical field where bacteriuria directly increases infection risk. 1

Non-Urologic Surgery (DO NOT TREAT)

Do not screen or treat ASB before: 1, 2

• Orthopedic surgery (including joint replacements)
• Cardiac surgery (including CABG)
• Vascular surgery
• General abdominal surgery
• Any other non-urologic procedure

Evidence basis: Three studies screening 3,167 preoperative patients found no benefit from treating ASB—postoperative prosthetic joint infections showed different pathogens than preoperative urine cultures, indicating the urine was not the infection source. 1 The baseline risk of symptomatic UTI without treatment was only 36 per 1,000 patients. 1

Low-Risk Urologic Procedures (DO NOT TREAT)

No treatment needed for: 1

• Diagnostic cystoscopy without biopsy/incision
• Simple catheter removal or exchange
• Removal of ureteral stents
• Urethral procedures without mucosal trauma

Special Urologic Implants

Do not screen or treat ASB for: 1

• Artificial urinary sphincter implantation
• Penile prosthesis implantation
• Patients living with implanted urologic devices

All patients should receive standard perioperative prophylaxis regardless of ASB status. 1

Orthopedic Surgery: A Common Pitfall

The 2019 IDSA guidelines explicitly state they cannot make a recommendation for or against adjusting perioperative prophylaxis to cover urinary pathogens in orthopedic implant patients because "the magnitudes of benefits and harms are so uncertain." 1 However, they strongly recommend against screening and treating ASB as a separate intervention beyond standard surgical prophylaxis. 1

An older 2003 joint guideline from urology and orthopedic societies suggested considering prophylaxis for high-risk patients (immunocompromised, first 2 years post-implant) undergoing high-risk urologic procedures, but this predates current evidence. 1

Practical approach: Do not screen for ASB before orthopedic surgery. If bacteriuria is incidentally discovered, do not treat it separately—just ensure standard perioperative prophylaxis is given. 1, 2

Harms of Unnecessary Treatment

Treating ASB when not indicated causes: 1, 3

• Increased antimicrobial resistance (reinfection with resistant organisms)
• Clostridioides difficile infection risk
• Drug adverse effects
• Increased healthcare costs
• No reduction in surgical site infections or mortality

Recent Contradictory Evidence

A 2025 UK study of 443 HoLEP patients found no urosepsis in 125 patients with untreated ASB (vs 0.6% in those without bacteriuria), challenging routine treatment even for mucosal-trauma procedures. 4 However, this single-center retrospective study contradicts the established guideline recommendation based on multiple RCTs showing 13% infection rates without treatment. 1 Until replicated in prospective trials, continue following IDSA guidelines to treat ASB before mucosal-trauma urologic procedures. 1

Similarly, a 2019 Colombian cohort found no association between ASB and postoperative infections in urologic surgery, 5 but this conflicts with higher-quality RCT evidence and should not change practice.

Key Clinical Pearls

• If bacteriuria is present preoperatively, the urine must be sterile before any mucosal-trauma urologic procedure—otherwise bacteremia risk increases dramatically. 1
• Pyuria accompanying ASB is NOT an indication for treatment in any surgical context. 6
• Polymicrobial bacteriuria (>2 organisms) usually represents contamination, not true infection, but should still be treated before high-risk urologic procedures if confirmed. 7
• A 2025 multicenter study found no difference between short (≤5 days) vs long (>5 days) preoperative antibiotic courses for ASB before urologic surgery, supporting the guideline recommendation for 1-2 doses only. 7