How is asymptomatic bacteriuria (asymptomatic bacterial infection of the urinary tract) managed?

Management of Asymptomatic Bacteriuria

Asymptomatic bacteriuria should not be screened for or treated in most patient populations, with only two specific exceptions: pregnant women and patients undergoing urologic procedures with mucosal breach.

Definition and Diagnosis

Asymptomatic bacteriuria (ASB) is defined as:

• The presence of bacteria in properly collected urine specimens (≥10^5 CFU/mL) from individuals without signs or symptoms attributable to urinary tract infection 1
• For women: Two consecutive voided specimens with the same bacterial strain 1
• For men: A single clean-catch specimen with ≥10^5 CFU/mL 1
• For catheterized specimens: ≥10^2 CFU/mL in either gender 1

Prevalence

The prevalence varies significantly across different populations:

• Healthy premenopausal women: 1.0-5.0% 1
• Pregnant women: 1.9-9.5% 1
• Diabetic patients: 9.0-27% in women, 0.7-11% in men 1
• Elderly persons in the community: 10.8-16% in women, 3.6-19% in men 1
• Elderly persons in long-term care facilities: 25-50% in women, 15-50% in men 1
• Patients with indwelling catheters (long-term): 100% 1

Screening and Treatment Recommendations

Populations Where Treatment IS Recommended:

1. Pregnant Women

   • Screen with urine culture at least once in early pregnancy 1
   • Treat if positive, even if asymptomatic 1, 2
   • Duration of therapy: 3-7 days 1
   • Follow up with periodic screening for recurrent bacteriuria 1
   • Rationale: Treatment reduces risk of pyelonephritis, preterm birth, and low birth weight 1

2. Patients Undergoing Urologic Procedures with Mucosal Breach

   • Screen before transurethral resection of the prostate 1
   • Screen before other urologic procedures where mucosal bleeding is anticipated 1, 2
   • Initiate antimicrobial therapy shortly before the procedure 1
   • Discontinue therapy after the procedure unless an indwelling catheter remains in place 1

Populations Where Treatment is NOT Recommended:

1. Premenopausal, non-pregnant women 1, 2
2. Diabetic patients 1, 2
3. Older persons living in the community 1
4. Elderly institutionalized individuals 1
5. Persons with spinal cord injury 1
6. Catheterized patients while the catheter remains in situ 1
7. Infants and children 1
8. Renal transplant recipients (insufficient evidence) 1

Important Clinical Considerations

Pyuria

• The presence of pyuria accompanying ASB is not an indication for antimicrobial treatment 1
• Pyuria does not reliably distinguish between ASB and symptomatic UTI in populations with high prevalence of bacteriuria 1

Nonspecific Symptoms in Elderly

• For older patients with functional/cognitive impairment who have bacteriuria and delirium or falls but no focal genitourinary symptoms, assess for other causes rather than treating the bacteriuria 1
• Mental status changes alone are not an indication for treating bacteriuria in the elderly 1

Antimicrobial Stewardship Considerations

• Treatment of ASB has been identified as a major contributor to inappropriate antimicrobial use 2, 3
• Unnecessary treatment promotes antimicrobial resistance 1, 2
• Treatment may disrupt protective bacterial colonization and lead to colonization with more resistant organisms 2, 3

Potential Harms of Treating ASB

1. Increased antimicrobial resistance 1, 2, 4
2. Adverse drug effects 1, 4
3. Risk of Clostridioides difficile infection, particularly in elderly 1
4. Potential for reinfection with more resistant organisms 4
5. Some evidence suggests ASB may actually protect against symptomatic UTI in certain populations 1

Conclusion

The management of asymptomatic bacteriuria has evolved significantly. Current evidence strongly supports a restrictive approach to both screening and treatment, limiting these interventions to only pregnant women and patients undergoing urologic procedures with mucosal breach. For all other populations, the potential harms of treatment outweigh any benefits.