Should a male with a normal urinalysis (UA) and a urine culture growing less than 10,000 cfu/ml of Streptococcus viridans be treated?

Management of Male with Normal UA and Low-Count Streptococcus viridans in Urine Culture

A male patient with a normal urinalysis and urine culture growing less than 10,000 CFU/mL of Streptococcus viridans should not be treated with antibiotics as this finding does not meet diagnostic criteria for a urinary tract infection (UTI).

Diagnostic Criteria for UTI

• According to established guidelines, the diagnosis of UTI requires both urinalysis results suggesting infection (pyuria or bacteriuria) AND the presence of at least 50,000 CFU/mL of a uropathogen cultured from a urine specimen 1
• For asymptomatic bacteriuria in men, a single specimen with ≥10^5 CFU/mL (100,000 CFU/mL) is required for diagnosis 2
• The patient in question has:
  • Normal urinalysis (no evidence of inflammation)
  • Low bacterial count (<10,000 CFU/mL)
  • Growth of Streptococcus viridans (not a typical uropathogen)

Significance of Findings

• Streptococcus viridans is not typically considered a primary uropathogen and at low colony counts is more likely to represent contamination 1, 2
• The absence of pyuria or bacteriuria on urinalysis makes a true UTI highly unlikely (<0.3% probability) 1
• The colony count of less than 10,000 CFU/mL falls well below the diagnostic threshold of 50,000-100,000 CFU/mL required for UTI diagnosis 1, 2

Risks of Unnecessary Treatment

• Treating asymptomatic bacteriuria or contamination can:
  • Contribute to antimicrobial resistance 1
  • Increase risk of future UTIs by disrupting protective flora 1
  • Lead to unnecessary medication side effects 3
  • Eradicate potentially protective bacterial strains 1

Special Considerations

• Even in populations where treatment of asymptomatic bacteriuria is recommended (pregnant women, patients before urological procedures with mucosal bleeding), the colony count threshold is still 10^5 CFU/mL (100,000 CFU/mL) 2
• European Association of Urology strongly recommends against treating asymptomatic bacteriuria in men without risk factors 1
• Unnecessary antimicrobial use is associated with increased risk of resistance, adverse events, and costs 3

Clinical Approach

• Document the normal urinalysis and low colony count findings
• If the patient is asymptomatic, no treatment is indicated 1, 2
• If the patient has urinary symptoms despite the normal UA and low colony count:
  • Consider alternative diagnoses for the symptoms
  • Evaluate for other urological conditions that might explain symptoms
  • Consider digital rectal examination to investigate prostate conditions 1

Conclusion

The combination of normal urinalysis and low colony count (<10,000 CFU/mL) of Streptococcus viridans does not meet diagnostic criteria for UTI and does not warrant antibiotic treatment. Treating such findings would contribute to antimicrobial resistance without providing clinical benefit.