Does an asymptomatic patient with a urine culture showing bacteriuria (bacterial colony count) require treatment?

Management of Asymptomatic Bacteriuria with Colony Count 50,000-100,000

Asymptomatic bacteriuria with a colony count of 50,000-100,000 CFU/mL should NOT be treated with antibiotics in most patient populations. 1

Definition and Diagnosis

• Asymptomatic bacteriuria is defined as the presence of significant bacteriuria without symptoms of urinary tract infection
• Diagnostic criteria:
  • Women: Two consecutive voided urine specimens with isolation of the same bacterial strain in quantitative counts ≥10^5 CFU/mL
  • Men: A single clean-catch voided urine specimen with one bacterial species isolated in a quantitative count ≥10^5 CFU/mL
  • Catheterized specimens: ≥10^2 CFU/mL 1

Evidence-Based Recommendations

Do NOT Screen or Treat in:

• Non-pregnant premenopausal women 1
• Diabetic patients 1
• Community-dwelling older adults 1
• Elderly institutionalized patients 1
• Patients with spinal cord injury/neurogenic lower urinary tract dysfunction 2
• Patients with indwelling catheters while the catheter remains in place 1

The American College of Physicians and the Infectious Diseases Society of America strongly recommend against treating asymptomatic bacteriuria with antibiotics in these populations as treatment does not improve clinical outcomes and may contribute to antimicrobial resistance 1.

Only Screen and Treat in:

1. Pregnant women - Screen in early pregnancy and treat if positive (3-7 days of therapy with follow-up) 1
2. Prior to urologic procedures with risk of mucosal bleeding - Particularly before transurethral resection of the prostate 1, 2

Rationale Against Treatment

1. Lack of clinical benefit: Treatment of asymptomatic bacteriuria does not:

   • Decrease frequency of symptomatic UTIs
   • Decrease hospitalizations
   • Prevent progression of complications 1

2. Potential harms:

   • Promotes antimicrobial resistance 3
   • Increases risk of antibiotic-associated adverse events 3
   • May lead to reinfection with more resistant organisms 2
   • Increases healthcare costs 3

3. High prevalence of inappropriate treatment: Studies show that 45% of asymptomatic bacteriuria cases receive inappropriate treatment 3

Common Pitfalls Leading to Overtreatment

Beware of these factors that often lead to unnecessary treatment:

• Female sex (2.11 times higher odds of receiving treatment) 3
• Isolation of gram-negative pathogens (3.58 times higher odds) 3
• Presence of pyuria (2.83 times higher odds) 3
• Positive nitrite test (3.83 times higher odds) 3
• Higher bacterial counts in culture (≥100,000 CFU/mL vs <10,000 CFU/mL) 3

Important: Pyuria accompanying asymptomatic bacteriuria is NOT an indication for antimicrobial treatment 1

Special Considerations for Neurogenic Lower Urinary Tract Dysfunction

The AUA/SUFU guideline specifically states: "Clinicians should not treat asymptomatic bacteriuria in patients with NLUTD" (Moderate Recommendation; Evidence Level: Grade C) 2

This recommendation is based on evidence that:

• Treatment of asymptomatic bacteriuria in catheter-free patients with spinal cord injury is followed by early recurrence of bacteriuria with more resistant strains
• Antibiotic resistance is a significant problem in these patients due to frequent antibiotic use 2

By avoiding unnecessary treatment of asymptomatic bacteriuria, clinicians can practice effective antibiotic stewardship while providing appropriate patient care.