Do we treat asymptomatic bacteriuria (bacteria in the urine) found in a urinalysis?

Asymptomatic Bacteriuria: Do Not Treat in Most Patients

In the vast majority of patients, asymptomatic bacteriuria (bacteria in the urine without symptoms) should NOT be treated with antibiotics. 1, 2

Two Exceptions Where Treatment IS Required

Treatment is indicated in only two specific clinical scenarios:

1. Pregnant Women

• Screen all pregnant women with urine culture at least once in early pregnancy 1, 2
• Treat if positive with 3-7 days of antimicrobial therapy 1, 2
• Perform periodic screening for recurrent bacteriuria following treatment 1
• This is the most important exception because untreated bacteriuria in pregnancy can lead to pyelonephritis and adverse pregnancy outcomes 2

2. Before Urologic Procedures with Mucosal Bleeding

• Screen and treat before transurethral resection of the prostate (TURP) 1, 2
• Screen and treat before any urologic procedure where mucosal bleeding is anticipated 1, 2
• Initiate antimicrobials shortly before the procedure 1, 2
• Stop antibiotics immediately after the procedure unless an indwelling catheter remains 1, 2
• This prevents bacteremia (occurs in up to 60% of bacteriuric patients) and sepsis (6-10% risk) 2

Populations Where Treatment Is NOT Recommended

Do not screen or treat asymptomatic bacteriuria in the following groups, even if bacteria are present:

• Premenopausal, nonpregnant women 1, 2
• Diabetic patients (both men and women) 1, 2
• Elderly patients living in the community 1, 2
• Nursing home residents 1, 2
• Patients with spinal cord injury 1, 2
• Catheterized patients while the catheter remains in place 1, 2
• Renal transplant recipients beyond 1 month post-transplant 3, 4
• Pediatric patients 5

The evidence is particularly strong for elderly patients: randomized trials showed similar rates of symptomatic UTI and mortality at 9 years between treated and untreated groups, but significantly more adverse drug events and resistant organisms in those who received antibiotics 2.

Critical Pitfall: Pyuria Is NOT an Indication for Treatment

The presence of white blood cells (pyuria) in the urine does NOT change management. 1, 5

• Pyuria accompanying asymptomatic bacteriuria is not an indication for antimicrobial treatment 1, 5
• Pyuria is commonly found in the absence of infection, particularly in older adults with incontinence 6
• Do not treat based on urinalysis showing "WBCs present" if the patient has no urinary symptoms 5

Special Consideration: Post-Catheter Removal

One nuanced exception exists for asymptomatic women with catheter-acquired bacteriuria:

• May consider treatment if bacteriuria persists 48 hours after catheter removal 1, 2
• This is based on one randomized trial showing improved outcomes at 14 days 2
• This recommendation is weaker than the others (B-I evidence) 1

Why Not Treating Is the Right Decision

Treating asymptomatic bacteriuria in non-indicated populations causes harm:

• Increases antimicrobial resistance 2, 4, 7
• Increases adverse drug effects including Clostridioides difficile infection 4, 7
• May eliminate protective bacterial strains that prevent symptomatic UTI 3, 8
• Research shows ABU is harmless and even protective against symptomatic infections 8

Diagnostic Criteria (For Reference)

If you need to confirm asymptomatic bacteriuria:

• Women: 2 consecutive voided specimens with same organism ≥10⁵ CFU/mL 1, 2
• Men: Single clean-catch specimen with ≥10⁵ CFU/mL 1, 2
• Catheterized specimens: Single specimen with ≥10² CFU/mL 1, 2
• Pregnant women: Any specimen with ≥10⁴ CFU/mL Group B Streptococcus 4

The key distinction is that the patient must be completely asymptomatic from a urinary standpoint—no dysuria, frequency, urgency, suprapubic pain, or fever attributable to the urinary tract 9, 7.