When to Treat Asymptomatic Bacteriuria
Treat asymptomatic bacteriuria only in pregnant women and patients undergoing urologic procedures with mucosal bleeding—do not treat in all other populations, as treatment provides no clinical benefit and increases antimicrobial resistance and adverse events. 1, 2
Populations Where Treatment IS Indicated
Pregnant Women (Strong Recommendation)
- 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 with standard short-course antimicrobial therapy or single-dose fosfomycin trometamol. 1, 3
- Perform periodic screening for recurrent bacteriuria following therapy throughout pregnancy. 1, 3
- Rationale: Untreated asymptomatic bacteriuria carries a 20-35% risk of pyelonephritis (reduced to 1-4% with treatment) and increases risk of preterm delivery and low birth weight. 3
Urologic Procedures with Mucosal Bleeding (Strong Recommendation)
- Screen for and treat asymptomatic bacteriuria before transurethral resection of the prostate and other urologic procedures breaching the mucosa. 1, 2
- Initiate antimicrobial therapy shortly before the procedure (the night before or immediately prior). 1, 2
- Do not continue antimicrobials after the procedure unless an indwelling catheter remains in place. 1, 2
- Rationale: Bacteremia occurs in up to 60% of bacteriuric patients undergoing these procedures, with sepsis in 6-10%. 2
Special Consideration: Catheter-Acquired Bacteriuria
- Consider treatment for asymptomatic women with catheter-acquired bacteriuria that persists 48 hours after catheter removal. 2
- This is based on one randomized trial showing improved outcomes at 14 days. 2
Populations Where Treatment IS NOT Indicated (Strong Recommendations)
Do NOT Screen or Treat in the Following Groups:
- Premenopausal, nonpregnant women 1, 2
- Patients with well-regulated diabetes mellitus (both women and men) 1, 2
- Postmenopausal women 1, 2
- Elderly institutionalized patients and older persons living in the community 1, 2
- Patients with spinal cord injury 1, 2
- Catheterized patients while the catheter remains in situ 1, 2
- Patients with dysfunctional and/or reconstructed lower urinary tract 1
- Renal transplant recipients 1, 4
- Patients before arthroplasty surgery 1
- Patients with recurrent urinary tract infections 1
- Patients before cardiovascular surgeries (weak recommendation) 1
Key Evidence Supporting Non-Treatment
Clinical Outcomes
- A 2015 Cochrane review of 9 studies (1614 participants) found no difference in symptomatic UTI development (RR 1.11), complications (RR 0.78), or death (RR 0.99) between antibiotic and no treatment groups. 5
- Treatment resulted in significantly more adverse events (RR 3.77) without clinical benefit. 5
- Randomized trials in elderly patients showed similar rates of symptomatic UTI and mortality at 9 years, but significantly more adverse drug events and resistant organisms in treated patients. 2
Protective Effect of Asymptomatic Bacteriuria
- Clinical studies demonstrate that asymptomatic bacteriuria may protect against superinfecting symptomatic UTI. 1
- Treatment risks eradicating potentially protective bacterial strains and selecting for antimicrobial resistance. 1, 6
Critical Pitfalls to Avoid
Pyuria Is NOT an Indication for Treatment
- Pyuria accompanying asymptomatic bacteriuria is not an indication for antimicrobial treatment. 1, 2, 4
- This is a common error that leads to unnecessary antibiotic use. 2
Do Not Confuse Nonspecific Symptoms with UTI
- In elderly patients with functional or cognitive impairment who have bacteriuria and delirium or falls, assess for other causes rather than treating the bacteriuria. 4
- Genitourinary symptoms in elderly women are not necessarily related to cystitis. 1
Diagnostic Criteria Matter
- For women: Requires 2 consecutive voided specimens with the same organism ≥10^5 CFU/mL 1, 2
- For men: Single clean-catch specimen with ≥10^5 CFU/mL 1, 2
- For catheterized specimens: Single specimen with ≥10^2 CFU/mL 1, 2