What is the treatment for Enterococcus faecalis bacteremia?

Treatment for Enterococcus faecalis Bacteremia

For Enterococcus faecalis bacteremia, the recommended first-line treatment is ampicillin or penicillin G combined with gentamicin for synergistic bactericidal activity, with treatment duration of 7-14 days for uncomplicated cases and up to 6 weeks for endocarditis or complicated infections. 1

Initial Assessment and Treatment Approach

Antimicrobial Selection

• First-line therapy (penicillin-susceptible strains):

  • Ampicillin 2g IV every 4 hours (preferred over penicillin G due to lower MICs) 1
  • PLUS gentamicin for synergistic effect 1, 2

• For penicillin-allergic patients:

  • Vancomycin should be used if the pathogen is resistant to ampicillin 1
  • Note that vancomycin is inferior to beta-lactams for susceptible strains 1

• For ampicillin and vancomycin-resistant enterococci:

  • Linezolid or daptomycin based on susceptibility testing 1
  • For daptomycin, higher doses (10-12 mg/kg/day) may be considered 1

Duration of Therapy

• Uncomplicated bacteremia: 7-14 days 1
• Complicated bacteremia or endocarditis: 4-6 weeks 1

Special Considerations

Catheter-Related Bloodstream Infections

• Short-term catheters: Remove infected catheter 1
• Long-term catheters:
  • Remove if there is insertion site/pocket infection, suppurative thrombophlebitis, sepsis, endocarditis, persistent bacteremia, or metastatic infection 1
  • If catheter is retained, use antibiotic lock therapy in addition to systemic antibiotics 1
  • Monitor with follow-up blood cultures; remove catheter if bacteremia persists >72 hours after appropriate therapy 1

Evaluation for Endocarditis

Perform transesophageal echocardiography (TEE) if:

• Signs/symptoms of endocarditis (new murmur, embolic phenomena)
• Persistent bacteremia or fever >72 hours despite appropriate antibiotics
• Radiographic evidence of septic pulmonary emboli
• Presence of prosthetic valve or other endovascular foreign bodies 1

Alternative Treatment Regimens

For Aminoglycoside-Resistant Strains

• Double β-lactam therapy: Ampicillin 2g IV every 4 hours PLUS ceftriaxone 2g IV every 12 hours for 6 weeks 1
  • This regimen avoids nephrotoxicity associated with aminoglycosides
  • Particularly useful for patients with renal impairment or abnormal cranial nerve VIII function 1

For High-Level Aminoglycoside Resistance (HLAR)

• Aminoglycosides should not be used if MIC >500 mg/L 1
• Consider streptomycin if still active 1
• Ampicillin-ceftriaxone combination is reasonable 1

Pitfalls and Caveats

1. Monotherapy inadequacy: Enterococci are highly resistant to antibiotic-induced killing, and monotherapy with cell wall-active agents is often insufficient for serious infections 1, 2

2. Prolonged therapy requirement: Eradication requires prolonged administration (up to 6 weeks) of synergistic bactericidal combinations 1

3. Resistance concerns: Monitor for development of resistance during therapy, particularly with newer agents like daptomycin and linezolid 3, 4

4. Persistent bacteremia: Enterococcal bacteremia that persists for >4 days has been independently associated with increased mortality 1

5. Endocarditis risk: While the risk of endocarditis as a complication of enterococcal bacteremia is relatively low (approximately 1.5%), it carries significant mortality and requires extended treatment 1

6. Catheter management: Inappropriate decisions regarding catheter retention vs. removal can lead to treatment failure and persistent infection 1

By following these evidence-based recommendations and being vigilant for complications, clinicians can effectively manage E. faecalis bacteremia while minimizing morbidity and mortality.