What is the empiric antibiotic treatment for a urinary tract infection (UTI) with a culture positive for Enterococcus faecalis and pending sensitivities?

Empiric Antibiotic Treatment for UTI with Enterococcus faecalis

For empiric treatment of a UTI with Enterococcus faecalis while awaiting sensitivities, ampicillin is the drug of choice, with alternatives of amoxicillin-clavulanate or nitrofurantoin for uncomplicated cases, and vancomycin for complicated cases or patients with beta-lactam allergies. 1

First-Line Treatment Options

Uncomplicated UTI with E. faecalis:

• Ampicillin: 500 mg orally every 6 hours for 7 days

  • First-line therapy for ampicillin-susceptible enterococcal UTIs 2
  • High urinary concentrations may overcome moderate resistance 2

• Alternatives for uncomplicated cases:

  • Nitrofurantoin: 100 mg orally twice daily for 5-7 days

    • Good activity against E. faecalis, including some vancomycin-resistant strains 2
    • Only for lower UTI (cystitis) due to poor tissue penetration

  • Fosfomycin: 3 g single oral dose

    • FDA approved for E. faecalis UTIs 1
    • Convenient single-dose regimen

Complicated UTI with E. faecalis:

• Ampicillin-sulbactam: 3 g IV every 6 hours

  • Effective against many E. faecalis strains 3
  • Low resistance rates compared to fluoroquinolones

• Vancomycin: 15-20 mg/kg IV every 12 hours

  • For patients with beta-lactam allergies or suspected resistant strains 1
  • Initial empiric therapy should be directed against E. faecalis 1

Treatment Algorithm Based on Clinical Scenario

1. Uncomplicated outpatient UTI:

   • Start with oral ampicillin or amoxicillin-clavulanate
   • Alternative: nitrofurantoin or fosfomycin if penicillin allergic

2. Complicated UTI or inpatient:

   • Start with IV ampicillin or ampicillin-sulbactam
   • Alternative: vancomycin if beta-lactam allergic or high risk for resistance

3. Healthcare-associated UTI:

   • Consider broader coverage with piperacillin-tazobactam or vancomycin 1
   • Empiric anti-enterococcal therapy is recommended for healthcare-associated infections 1

4. Adjust therapy when sensitivities return:

   • Narrow therapy based on susceptibility results 1
   • De-escalate to oral therapy when clinically improved

Important Considerations

Resistance Patterns

• E. faecalis has lower rates of resistance to ampicillin compared to E. faecium 1
• Fluoroquinolone resistance is common in E. faecalis (47% resistance to ciprofloxacin in some studies) 3
• Avoid empiric fluoroquinolones due to increasing resistance rates 4

Special Populations

• Immunocompromised patients: Consider broader empiric coverage with vancomycin 1
• Patients with valvular heart disease: Ensure adequate enterococcal coverage 1
• Recent cephalosporin exposure: Higher risk for enterococcal infection, ensure coverage 1

Duration of Therapy

• Uncomplicated lower UTI: 5-7 days
• Complicated UTI/pyelonephritis: 7-14 days 5
• Adjust duration based on clinical response

Common Pitfalls to Avoid

1. Misinterpreting colonization as infection:

   • Distinguish between asymptomatic bacteriuria and true infection 1
   • Avoid unnecessary treatment of asymptomatic bacteriuria

2. Inadequate empiric coverage:

   • E. faecalis is intrinsically resistant to cephalosporins and TMP-SMX
   • Ensure appropriate enterococcal coverage in high-risk patients

3. Overuse of broad-spectrum agents:

   • Narrow therapy once susceptibilities are available 1
   • Use shortest effective duration of therapy

4. Relying on fluoroquinolones:

   • High resistance rates make them poor empiric choices for E. faecalis UTIs 3, 4

By following this approach, you can provide effective empiric coverage for E. faecalis UTI while awaiting susceptibility results, optimizing outcomes related to morbidity, mortality, and quality of life.