Do we treat asymptomatic urinary tract infections (UTIs)?

Management of Asymptomatic Bacteriuria (ASB)

Asymptomatic bacteriuria should not be treated except in pregnant women and before urological procedures that breach the mucosa. 1

Definition and Diagnosis

• Asymptomatic bacteriuria (ASB) is defined as:
  • In women: bacterial growth >10^5 CFU/mL in two consecutive urine samples without urinary symptoms 1
  • In men: bacterial growth >10^5 CFU/mL in a single urine sample without urinary symptoms 1
• ASB represents commensal colonization rather than infection requiring treatment 1

Evidence-Based Recommendations

Do NOT Screen or Treat ASB in:

• Women without risk factors
• Patients with well-regulated diabetes mellitus
• Postmenopausal women
• Elderly institutionalized patients
• Patients with dysfunctional/reconstructed lower urinary tract
• Renal transplant recipients
• Patients before arthroplasty surgery
• Patients with recurrent UTIs
• Patients before cardiovascular surgeries

DO Screen and Treat ASB in:

1. Pregnant women - Use standard short-course treatment or single-dose fosfomycin trometamol 1
2. Before urological procedures breaching the mucosa 1

Rationale for Not Treating ASB

1. Protection against symptomatic UTI: Clinical studies show ASB may protect against superinfecting symptomatic UTIs 1
2. Antimicrobial resistance risk: Treating ASB increases risk of selecting antimicrobial-resistant organisms 1
3. Potential harm: Treatment of ASB may be harmful by eradicating potentially protective bacterial strains 1
4. Limited evidence of benefit: Most studies showing benefit are older with low methodological quality; newer studies with higher methodological quality show less evident benefits 1

Special Considerations

Pediatric Population

• In children aged 2-24 months, ASB should not be treated 1
• The AAP guidelines specifically note that "treatment of asymptomatic bacteriuria may be harmful" 1

Pregnancy

• Screen and treat ASB in pregnant women with standard short-course antibiotics or single-dose fosfomycin trometamol 1, 2
• This recommendation is based on historical data showing reduced risk of pyelonephritis, though recent evidence suggests the benefits may be less evident than previously thought 1

Elderly Patients

• ASB is common in elderly institutionalized patients and should not be treated 1, 2
• Genitourinary symptoms in elderly women are not necessarily related to UTI 1

Common Pitfalls to Avoid

1. Overdiagnosis and overtreatment: Treating bacteriuria without symptoms contributes to antimicrobial resistance
2. Misinterpreting pyuria: Pyuria is commonly found in the absence of infection, particularly in older adults with lower urinary tract symptoms 3
3. Treating based on positive urine culture alone: Remember that ASB is common, particularly in older women, and should not be treated with antibiotics 3
4. Ignoring local resistance patterns: When treatment is indicated, consider local antimicrobial sensitivity patterns 1

Conclusion

The evidence strongly supports not treating asymptomatic bacteriuria in most populations. Treatment should be reserved only for pregnant women and patients undergoing urological procedures that breach the mucosa. This approach aligns with antimicrobial stewardship principles and helps prevent the development of antimicrobial resistance.