Do Not Treat Asymptomatic Bacteriuria with High WBC Count
Patients with bacteriuria and elevated white blood cell counts in the urine but no symptoms should NOT receive antibiotic treatment, as this represents asymptomatic bacteriuria (ASB) which does not benefit from antimicrobial therapy and increases risks of antimicrobial resistance and adverse drug effects. 1
Key Diagnostic Principle
The presence of bacteria and pyuria (high WBC) in urine without symptoms defines asymptomatic bacteriuria, not a urinary tract infection requiring treatment. 1 The critical distinction is the absence of UTI-specific symptoms such as:
- Dysuria (burning with urination)
- Urinary frequency or urgency
- Suprapubic pain
- Fever
- Flank pain
- Gross hematuria
- New or worsening urinary incontinence 1
Strong Recommendation Against Treatment
The 2019 IDSA guidelines provide a strong recommendation against screening for or treating asymptomatic bacteriuria in most patient populations (strong recommendation, moderate-quality evidence). 1 This applies to:
- Older patients with functional/cognitive impairment 1
- Patients with spinal cord injury 1
- Patients with short-term indwelling catheters (<30 days) 1
- Patients with long-term indwelling catheters 1
- Nonpregnant women of all ages 1
- Elderly institutionalized patients 1
- Patients undergoing elective nonurologic surgery 1
Why Treatment is Harmful
Treating asymptomatic bacteriuria causes more harm than benefit by:
- Increasing antimicrobial resistance: Unnecessary antibiotic exposure selects for resistant organisms 1, 2
- Causing adverse drug effects: Including allergic reactions, gastrointestinal symptoms, and drug interactions 1
- Risking Clostridioides difficile infection: Particularly in vulnerable populations 1
- Providing no clinical benefit: Multiple studies show no reduction in symptomatic UTI, renal damage, or mortality 2
- Potentially removing protective bacteria: In women with recurrent UTIs, ASB may actually prevent symptomatic episodes 3
Special Populations Requiring Treatment
Only two specific populations benefit from treating asymptomatic bacteriuria:
- Pregnant women: Treatment decreases risk of symptomatic UTI, low birthweight, and preterm delivery 2
- Patients undergoing urologic procedures with mucosal trauma: Such as transurethral resection surgery, where treatment reduces postoperative UTI risk 1, 2
Clinical Pitfalls to Avoid
Do not order surveillance urine cultures in asymptomatic patients. 1 This common error leads to unnecessary treatment of colonization rather than infection.
Do not treat based solely on laboratory findings. Pyuria (≥10 WBCs/high-power field) and positive urine cultures are nearly universal in catheterized patients and common in elderly patients without infection. 1 These findings have poor positive predictive value for actual infection in asymptomatic individuals. 1
Do not confuse nonspecific symptoms with UTI. In elderly patients, symptoms like confusion, falls, anorexia, or functional decline are often attributed to UTI but are rarely caused by bacteriuria. 1 Assess for other causes first rather than treating bacteriuria. 1
When to Reconsider
If a patient develops systemic signs of infection (fever >38°C, hemodynamic instability, rigors) or local genitourinary symptoms, this is no longer asymptomatic bacteriuria and requires evaluation and treatment as a symptomatic UTI. 1
For patients with recurrent symptomatic UTIs, do not treat intervening periods of asymptomatic bacteriuria. 1, 3 Treatment of ASB in this population is associated with higher occurrence of antibiotic-resistant bacteria and provides no benefit. 3