What alternative antibiotics can be used for a patient with a wound culture growing Enterococcus faecium sensitive to ampicillin and vancomycin?

Alternative Antibiotics for Enterococcus faecium Wound Infection

For a patient with a wound culture growing Enterococcus faecium sensitive to ampicillin and vancomycin, linezolid or daptomycin should be used as alternative antibiotics based on susceptibility testing. 1

First-line Recommendations

• Ampicillin is the drug of choice for ampicillin-susceptible enterococci, and vancomycin should be used if the pathogen is resistant to ampicillin 1
• If these first-line options cannot be used, the following alternatives are recommended:

Alternative Options

Linezolid

• FDA-approved for vancomycin-resistant enterococcal infections 2
• Dosing: 600 mg IV or orally every 12 hours 2
• Bacteriostatic against enterococci 1
• Demonstrated 67% cure rate in high-dose treatment of vancomycin-resistant enterococcal infections 3
• Monitoring considerations: Watch for bone marrow suppression, neuropathy, and drug interactions with prolonged use 1

Daptomycin

• Bactericidal against susceptible enterococcal strains 4
• Recommended dose: 10-12 mg/kg/day for enterococcal infections 1
• Particularly useful for invasive infections requiring bactericidal activity 1
• Monitoring considerations: Monitor CPK levels and watch for myopathy 4

Clinical Considerations

• Susceptibility testing should include penicillin/ampicillin, vancomycin (MIC determination), and testing for high-level resistance to gentamicin 1
• For multidrug-resistant enterococcal infections, consultation with infectious disease specialists is strongly recommended 5
• Duration of therapy for uncomplicated enterococcal wound infections is typically 7-14 days 1

Special Situations

• For severe infections or bacteremia, consider combination therapy:
  • Daptomycin combined with ampicillin or ceftaroline may have synergistic activity against resistant strains 1
  • Higher daptomycin doses (10-12 mg/kg/day) may be more effective for serious infections 1

Emerging Options

• Quinupristin/dalfopristin has activity against E. faecium (but not E. faecalis) and can be considered if available 3
• Tigecycline has in vitro activity against many enterococcal strains 6

Common Pitfalls

• Avoid monotherapy with daptomycin for severe enterococcal infections; consider combination therapy for better outcomes 1
• Linezolid resistance can emerge during therapy, particularly with prolonged use 7
• Remember that E. faecium has higher rates of antimicrobial resistance compared to E. faecalis 1
• Enterococci are intrinsically resistant to cephalosporins when used as monotherapy 1