What is the treatment for Enterococcus bacteremia after antibiotic (Abx) therapy?

Treatment of Enterococcus Bacteremia After Antibiotic Therapy

For Enterococcus bacteremia after antibiotic therapy, ampicillin is the drug of choice for ampicillin-susceptible strains, while vancomycin should be used for ampicillin-resistant strains; for both ampicillin and vancomycin-resistant enterococci, linezolid or daptomycin should be used based on susceptibility testing. 1, 2

First-line Treatment Options

• Ampicillin is the preferred first-line agent for ampicillin-susceptible Enterococcus faecalis infections 1, 3
• Vancomycin should be used if the pathogen is resistant to ampicillin 1
• For both ampicillin and vancomycin-resistant enterococci (VRE), linezolid or daptomycin should be used based on susceptibility testing 1, 4
• High-dose daptomycin (8-12 mg/kg IV daily) can be considered for VRE bacteremia, potentially in combination with beta-lactams 1

Treatment Duration and Approach

• For uncomplicated enterococcal bacteremia, a 7-14 day course of therapy is recommended when:
  • The catheter is removed, or
  • A long-term catheter is retained and antibiotic lock therapy is used 1, 2
• Longer treatment courses are required for endocarditis or metastatic infections 2
• Enterococcal bacteremia that persists for >4 days has been independently associated with increased mortality, requiring aggressive management 1

Management of Intravascular Catheters

• Removal of infected short-term intravascular catheters is recommended 1
• Removal of infected long-term catheters should be done in cases of:
  • Insertion site or pocket infection
  • Suppurative thrombophlebitis
  • Sepsis
  • Endocarditis
  • Persistent bacteremia
  • Metastatic infection 1
• If a long-term catheter is retained, antibiotic lock therapy should be used in addition to systemic therapy 1
• Patients with enterococcal catheter-related bloodstream infection (CRBSI) involving a long-term catheter for whom the catheter is retained should have follow-up blood cultures and catheter removal if persistent bacteremia (>72 h after the initiation of appropriate antibiotic therapy) is detected 1

Evaluation for Endocarditis

• For enterococcal CRBSI, a transesophageal echocardiography (TEE) should be performed if the patient has:
  • Signs and symptoms that suggest endocarditis (e.g., new murmur or embolic phenomena)
  • Prolonged bacteremia or fever, despite appropriate antimicrobial therapy (e.g., bacteremia or fever >72 h after the onset of appropriate antibiotic therapy)
  • Radiographic evidence of septic pulmonary emboli
  • Presence of a prosthetic valve or other endovascular foreign bodies 1

Combination Therapy Considerations

• The role of combination therapy (i.e., a cell wall–active antimicrobial and an aminoglycoside) for treating enterococcal CRBSI without endocarditis is unresolved 1
• One large series found that combination therapy with gentamicin and ampicillin was more effective than monotherapy when the catheter was retained in cases of enterococcal CRBSI 1
• For aminoglycoside-resistant strains, ampicillin plus ceftriaxone can be considered 3

Common Pitfalls and Caveats

• Enterococci are intrinsically resistant to cephalosporins when used alone 3
• Prior treatment with antibiotics such as cephalosporins or quinolones is a risk factor for enterococcal infections 5
• Inadequate treatment duration, especially in cases with endovascular infection, should be avoided 2
• Failure to remove infected catheters when indicated can lead to persistent infection 1
• Not performing TEE when indicated may result in missed diagnosis of endocarditis 1, 2
• Delayed administration of appropriate antibiotics is associated with increased mortality in VRE bacteremia 6

Emerging Therapies

• For recurrent or refractory enterococcal bacteremia, bacteriophage therapy in combination with antibiotics has shown promise in case reports 7
• Newer agents like oritavancin and dalbavancin may have a role in treatment of resistant enterococcal infections 8