What is the recommended treatment for Enterococcal infections?

Treatment of Enterococcal Infections

The recommended first-line treatment for enterococcal infections is a combination of ampicillin or penicillin G with gentamicin for susceptible strains, with treatment duration of 4-6 weeks for endocarditis and shorter courses for other infections based on clinical response. 1

Treatment Algorithm Based on Susceptibility

For Penicillin/Ampicillin-Susceptible Enterococci:

• First-line therapy:

  • Ampicillin 2g IV every 4 hours (or 200 mg/kg/day divided every 6 hours) 2
  • PLUS gentamicin 15 mg/kg/day IV/IM in 2-3 divided doses 1
  • Duration: 4-6 weeks for endocarditis; 7-14 days for uncomplicated infections 2

• Alternative for aminoglycoside-resistant strains:

  • Ampicillin 2g IV every 4 hours
  • PLUS ceftriaxone 2g IV every 12 hours 1
  • Duration: 6 weeks regardless of symptom duration 1

For Penicillin-Allergic Patients:

• Vancomycin 30 mg/kg/day IV in 2 divided doses
• PLUS gentamicin 15 mg/kg/day IV/IM in 2 divided doses 1, 2
• Duration: 6 weeks for endocarditis 1

For Vancomycin-Resistant Enterococci (VRE):

• First-line:

  • High-dose daptomycin 8-12 mg/kg IV daily (preferred for bloodstream infections) 1, 2
  • Consider combination with β-lactams for high daptomycin MICs 2

• Alternatives:

  • Linezolid 600 mg IV/PO every 12 hours 1, 3
  • Tigecycline 100 mg IV loading dose, then 50 mg IV every 12 hours (for intra-abdominal infections) 1

For Uncomplicated Urinary Tract Infections due to VRE:

• Single-dose fosfomycin 3g PO 1
• OR nitrofurantoin 100 mg PO every 6 hours 1
• OR high-dose ampicillin (if susceptible) 1

Special Considerations

For Endocarditis:

• Native valve endocarditis: 4-6 weeks of therapy 1
• Prosthetic valve endocarditis: Minimum 6 weeks of therapy 1
• For symptoms <3 months: 4 weeks may be sufficient if using ampicillin-gentamicin 1
• For symptoms >3 months: 6 weeks recommended 1

For Specific Infection Sites:

• Bloodstream infections: 10-14 days of therapy 2
• Intra-abdominal infections: Tigecycline is an effective option for VRE 1
• Urinary tract infections: Shorter courses (7-10 days) are typically sufficient 2

Monitoring and Precautions

• Monitor renal function weekly with aminoglycoside therapy 1, 2
• For daptomycin, monitor creatine kinase (CK) levels regularly 2
• Streptomycin should be avoided in patients with creatinine clearance <50 mL/min 1
• Enterococci are intrinsically resistant to cephalosporins when used alone 2

Important Caveats

• Infectious disease consultation is strongly recommended for management of enterococcal endocarditis 1
• Combination therapy is necessary for bactericidal activity against enterococci 2, 4
• Cephalosporins alone are ineffective against enterococci 2, 5
• Enterococcal superinfection can occur after cephalosporin therapy 5
• The ampicillin-ceftriaxone combination has shown promising results for orthopedic infections due to E. faecalis 6
• Treatment duration should never be shortened below recommended minimums, as this may lead to treatment failure 2

For severe infections, especially endocarditis, the synergistic combination of cell wall-active agents with aminoglycosides remains the cornerstone of therapy, with ampicillin-ceftriaxone emerging as an effective alternative for aminoglycoside-resistant strains 1, 7.