Do we treat asymptomatic bacteriuria with E. coli (>100,000 colony-forming units per milliliter (CFU/mL)) in an asymptomatic male?

Management of Asymptomatic Bacteriuria with E. coli in Males

Asymptomatic bacteriuria with E. coli in males should not be treated with antibiotics. 1

Definition and Diagnosis

• Asymptomatic bacteriuria (ASB) is defined as the presence of bacteria in the urine at specified quantitative counts (≥10^5 CFU/mL) in the absence of signs or symptoms attributable to urinary tract infection 1
• For males, a single clean-catch voided urine specimen with one bacterial species isolated in a quantitative count of ≥10^5 CFU/mL is sufficient to diagnose ASB 1
• The presence of pyuria with ASB is not an indication for antimicrobial treatment 1

Prevalence in Males

• ASB is rare in healthy young men 1
• The prevalence increases substantially after age 60, reaching 6-15% in men aged 75 years living in the community 1
• In long-term care facilities, 15-40% of elderly men have ASB 1
• The increased prevalence in older men is primarily due to obstructive uropathy and voiding dysfunction associated with prostatic hypertrophy 1

Evidence Against Treatment

The IDSA guidelines provide clear recommendations against screening for or treating ASB in most populations, including men, based on the following rationale:

1. Lack of benefit: Treatment of ASB has not been shown to prevent subsequent symptomatic episodes 2

2. Potential harms of treatment:

   • Promotes emergence of resistant organisms 2
   • Associated with antimicrobial adverse effects 2
   • May increase short-term frequency of symptomatic infection 3
   • Can lead to reinfection with organisms of increased antimicrobial resistance 3

3. Natural history: E. coli strains isolated from patients with ASB typically have fewer virulence characteristics than those causing symptomatic infections 1

Special Considerations

While the general recommendation is against treatment, there are specific scenarios where screening and treatment of ASB may be warranted:

• Prior to genitourinary procedures: Consider treatment before invasive genitourinary procedures where mucosal bleeding is anticipated 1, 2

• Renal transplant recipients: Screening may be recommended, though benefits are less clear 3

• Neutropenic patients: Consider individual assessment, though virulence factors alone cannot discriminate between symptomatic and asymptomatic bacteriuria 4

Clinical Pearls and Pitfalls

Common Pitfalls:

• Treating ASB due to misinterpretation of laboratory results
• Confusing cloudy or malodorous urine as signs of infection requiring treatment
• Attributing nonspecific symptoms to bacteriuria in elderly patients with multiple comorbidities

Important Considerations:

• Patient factors such as dementia and chronic pulmonary disease are more predictive of ASB than bacterial characteristics 4
• Bacterial virulence factors cannot reliably discriminate between symptomatic and asymptomatic bacteriuria 4
• The absence of pyuria does not reliably predict ASB and should not guide treatment decisions 4

In conclusion, current evidence strongly supports not treating asymptomatic bacteriuria with E. coli in males, regardless of bacterial count, unless the patient is undergoing an invasive genitourinary procedure.