When should asymptomatic bacteriuria (≥10⁵ CFU/mL) be treated in healthy non‑pregnant adults, pregnant women, patients undergoing urologic procedures, and immunocompromised or catheterized patients?

Asymptomatic Bacteriuria Treatment

Asymptomatic bacteriuria (≥10⁵ CFU/mL) should be treated ONLY in pregnant women and patients undergoing urologic procedures with anticipated mucosal bleeding—all other populations, including immunocompromised and catheterized patients, should NOT be treated. 1, 2

Populations Requiring Treatment

Pregnant Women

• Screen all pregnant women with urine culture at least once in early pregnancy and treat if positive. 1, 2
• Treatment duration should be 3-7 days of antibiotics. 1
• Perform periodic screening for recurrent bacteriuria following therapy to detect reinfection. 1
• Evidence shows treatment reduces symptomatic UTI, low birthweight, and preterm delivery risk. 3

Patients Undergoing Urologic Procedures with Mucosal Bleeding

• Screen with urine culture before the procedure and use targeted antimicrobial therapy based on culture results rather than empirical treatment. 1
• Initiate antimicrobials 30-60 minutes before the procedure (not the night before). 1, 2
• Discontinue immediately after the procedure unless an indwelling catheter remains in place. 1
• If a catheter remains post-procedure, continue antimicrobials until catheter removal. 1
• This approach prevents bacteremia (which occurs in up to 60% of bacteriuric patients) and sepsis (6-10% risk). 1
• Treatment before transurethral resection surgery specifically reduces postoperative UTI risk. 3

Special Consideration: Post-Catheter Removal

• Consider treatment for asymptomatic women with catheter-acquired bacteriuria persisting 48 hours after catheter removal, as one trial showed improved microbiologic and clinical outcomes at 14 days. 1, 2
• A 3-day regimen may be sufficient for women ≤65 years without upper tract symptoms. 1

Populations Where Treatment is NOT Recommended

Catheterized Patients

• Never treat asymptomatic bacteriuria while the catheter remains in situ, as 100% of catheterized patients eventually develop bacteriuria due to biofilm formation. 1, 2
• This applies to both short-term (<30 days) and long-term indwelling catheters. 1
• Replace catheters that have been in place ≥2 weeks before starting treatment if symptomatic UTI develops, as biofilms prevent accurate assessment. 1

Immunocompromised Patients

• Do not treat asymptomatic bacteriuria in immunocompromised patients (except solid organ transplant recipients where evidence is insufficient). 2
• This includes diabetic patients—diabetic women specifically do not require treatment for asymptomatic bacteriuria. 1, 2

Elderly Patients

• Do not screen or treat asymptomatic bacteriuria in elderly persons living in the community or institutionalized settings. 1, 2
• Randomized trials showed no difference in symptomatic UTI or mortality between treated and untreated groups. 2
• Treated patients had significantly more adverse drug events and resistant organisms. 2

Other Populations Not Requiring Treatment

• Premenopausal, nonpregnant women should not be treated, as asymptomatic bacteriuria does not predict future symptomatic infections. 1, 2
• Patients with spinal cord injuries should not be treated—78% had positive cultures but minimal symptomatic episodes, all responding promptly when actually symptomatic. 1, 2
• Patients undergoing non-urological elective surgery (including joint replacement) do not require screening or treatment. 1, 3
• Patients undergoing implantation of artificial urinary sphincter or penile prosthesis do not require treatment. 1

Critical Pitfalls to Avoid

Pyuria is NOT an Indication for Treatment

• Pyuria accompanying asymptomatic bacteriuria is NOT an indication for antimicrobial treatment, even with high CFU counts. 1, 2
• Do not diagnose or treat based on pyuria alone, even when bacteria are present. 4

Avoid Inappropriate Screening

• Do not use routine dipstick or urinalysis for screening—urine culture is required for definitive diagnosis. 2, 4
• Dipstick testing can lead to unnecessary treatment and antimicrobial resistance. 2

Harms of Treating Asymptomatic Bacteriuria

• Treatment in non-indicated populations leads to increased antimicrobial resistance, Clostridioides difficile infection, adverse drug events, and disruption of normal microbiome. 2
• For patients with recurrent UTI, treatment of asymptomatic bacteriuria is actually harmful. 3
• Asymptomatic bacteriuria may be protective against symptomatic UTI episodes. 5

Diagnostic Criteria for Reference

Women (Non-Catheterized)

• Two consecutive voided urine specimens showing ≥10⁵ CFU/mL of the same bacterial strain. 1, 4

Men (Non-Catheterized)

• Single clean-catch voided specimen showing ≥10⁵ CFU/mL of one bacterial species. 1, 4

Catheterized Specimens

• Single catheterized specimen showing ≥10² CFU/mL of one bacterial species. 1, 4