What is the recommended treatment for Enterococcus (E.) faecalis bacteremia with previous antibiotics treatment?

Treatment of Enterococcus faecalis Bacteremia

For Enterococcus faecalis bacteremia, the recommended first-line treatment is ampicillin plus ceftriaxone for 4-6 weeks, particularly when dealing with aminoglycoside-resistant strains or in patients with renal impairment. 1

Treatment Algorithm Based on Susceptibility and Clinical Scenario

First-Line Treatment Options:

• Ampicillin-susceptible E. faecalis:

  • Preferred regimen: Ampicillin 2g IV every 4 hours PLUS ceftriaxone 2g IV every 12 hours for 6 weeks 1
  • This double β-lactam combination is particularly valuable for:
    • Patients with renal impairment
    • Aminoglycoside-resistant strains
    • Patients with abnormal cranial nerve VIII function
    • Cases where aminoglycoside serum concentration monitoring is unavailable

• Alternative for streptomycin-susceptible/gentamicin-resistant strains:

  • Ampicillin 2g IV every 4 hours (or penicillin G 18-30 million units/24h IV) PLUS streptomycin 15 mg/kg/day in 2 divided doses for 4-6 weeks 1
  • Important caveat: Avoid streptomycin in patients with creatinine clearance <50 mL/min 1

For Penicillin-Allergic Patients:

• Vancomycin 30 mg/kg/day IV in 2 divided doses PLUS gentamicin 3 mg/kg/day IV in 3 divided doses for 6 weeks 1, 2
• Note: Vancomycin should only be used when β-lactams cannot be tolerated, as penicillin/ampicillin combinations are more effective 1

Duration of Therapy:

• Native valve endocarditis (NVE):
  • 4 weeks if symptoms <3 months and using ampicillin/penicillin plus gentamicin
  • 6 weeks if symptoms >3 months or using ampicillin plus ceftriaxone 1
• Prosthetic valve endocarditis (PVE): 6 weeks minimum 1
• Non-endocarditis bacteremia: Treatment duration should be individualized based on source control and clinical response

Special Considerations

For Vancomycin-Resistant Enterococci (VRE):

• Linezolid 600 mg IV/PO every 12 hours 1
• Daptomycin 8-12 mg/kg/day (high dose), potentially in combination with β-lactams 1, 3
• For uncomplicated urinary tract VRE infections:
  • Fosfomycin 3g PO single dose
  • Nitrofurantoin 100 mg PO every 6 hours
  • High-dose ampicillin (if susceptible) 1

Monitoring and Pitfalls:

• Renal function monitoring is critical, especially with aminoglycoside-containing regimens
• Advantages of ampicillin-ceftriaxone regimen:
  • Lower risk of nephrotoxicity
  • No need for aminoglycoside serum concentration monitoring 1
• Potential disadvantage: Possibility of hypersensitivity reactions to two separate β-lactams 1

Source Control:

• Always evaluate for and address potential sources of ongoing infection:
  • Endocarditis
  • Intra-abdominal or pelvic abscesses
  • Urinary tract infections
  • Indwelling devices/catheters

Evidence Quality and Considerations

The recommendations are primarily based on American Heart Association guidelines for infective endocarditis 1, which provide the most comprehensive guidance for E. faecalis bacteremia treatment. These guidelines are supported by European Society of Cardiology recommendations 1 and pediatric guidelines 1.

The ampicillin-ceftriaxone regimen has demonstrated similar success rates to aminoglycoside-containing regimens with lower nephrotoxicity 1. This is particularly important since many patients with enterococcal bacteremia are older or have compromised renal function.

Infectious disease consultation is strongly recommended for management of enterococcal infections, particularly for complex cases or those involving antimicrobial resistance 1.