Should patients with Strep viridans (Streptococcus viridans) in their urine culture be treated with antibiotics or monitored with increased fluid intake?

Management of Strep Viridans in Urine Culture Results

Strep viridans isolated from urine culture typically represents contamination rather than true urinary tract infection and does not require antibiotic treatment in most cases. Instead, increased fluid intake and monitoring is the appropriate management approach.

Understanding Strep Viridans in Urine

Streptococcus viridans is not a typical urinary pathogen and its presence in urine cultures usually indicates one of the following:

• Contamination during sample collection
• Colonization without infection
• Transient bacteremia with renal excretion

Key Considerations

• Strep viridans is primarily an oral commensal organism
• Not recognized as a common uropathogen in any major guidelines
• Lacks the virulence factors typically associated with urinary tract infections

Evidence-Based Approach

The 2019 Infectious Diseases Society of America (IDSA) guidelines for asymptomatic bacteriuria emphasize the importance of not treating asymptomatic bacteriuria in most patient populations 1. While these guidelines don't specifically address Strep viridans, the principles apply:

• Treating asymptomatic bacteriuria does not improve outcomes in most populations
• Unnecessary antibiotic use promotes antimicrobial resistance
• Antibiotics carry risks of adverse effects and C. difficile infection

Management Algorithm

1. Assess for symptoms of UTI:

   • If patient has fever, dysuria, frequency, urgency, or suprapubic pain → Consider treatment only if no other source explains symptoms
   • If asymptomatic → Do not treat, increase fluid intake only

2. Evaluate sample quality:

   • Presence of epithelial cells or multiple organisms → Suggests contamination
   • Clean-catch midstream specimen with proper technique → Repeat if clinical suspicion warrants

3. Consider patient-specific factors:

   • Immunocompromised status
   • Pregnancy
   • Planned urologic procedures with mucosal trauma (in which case treatment would be indicated) 1

Special Circumstances

For patients undergoing invasive urologic procedures with mucosal trauma:

• Screen for and treat bacteriuria prior to procedure 1
• Use targeted antimicrobial therapy based on susceptibility testing
• Short course (1-2 doses) is preferred over prolonged therapy 1

Antibiotic Options (Only if Treatment Indicated)

If treatment is deemed necessary due to special circumstances:

• Amoxicillin or amoxicillin-clavulanate are typically effective against Strep viridans 2, 3
• Penicillin resistance has been reported in up to 38% of viridans streptococci 4
• For penicillin-resistant strains, imipenem, cefotaxime, or ceftriaxone may be effective 3

Common Pitfalls to Avoid

1. Treating contamination or colonization with antibiotics
2. Failure to distinguish between true infection and presence of organisms
3. Not considering the clinical context when interpreting urine culture results
4. Overuse of antibiotics leading to resistance and adverse effects

Remember that the presence of bacteria in urine without symptoms (asymptomatic bacteriuria) rarely requires treatment, and Strep viridans specifically is an unusual urinary pathogen that most commonly represents contamination rather than infection.