What is the recommended treatment for Enterococcus (bacteria) bacteremia?

Treatment of Enterococcus Bacteremia

For enterococcal bacteremia, ampicillin is the drug of choice for ampicillin-susceptible enterococci, while vancomycin should be used for ampicillin-resistant strains. 1

Initial Antimicrobial Therapy

• For ampicillin-susceptible Enterococcus faecalis (most common cause of enterococcal bacteremia), ampicillin is the preferred first-line treatment 1, 2
• For ampicillin-resistant strains, vancomycin is the recommended alternative 1
• For both ampicillin and vancomycin-resistant enterococci (VRE), linezolid or daptomycin should be used based on susceptibility testing 1, 3, 4
• Piperacillin-tazobactam is another effective option for susceptible enterococcal bacteremia 2

Treatment Duration and Approach

• For uncomplicated enterococcal bacteremia (without endocarditis):

  • A 7-14 day course of therapy is recommended when the catheter is removed or when a long-term catheter is retained and antibiotic lock therapy is used 1
  • Shorter courses (7-10 days) may be sufficient for uncomplicated cases with good clinical response 5

• For complicated enterococcal bacteremia:

  • Longer treatment courses are required for endocarditis or metastatic infections 1, 6
  • Follow-up blood cultures should be obtained to document clearance of bacteremia 1

Management of Intravascular Catheters

• Short-term intravascular catheters should be removed when infected with enterococci 1
• Long-term catheters should be removed 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
  • Follow-up blood cultures are essential, with catheter removal if bacteremia persists >72 hours after initiation of appropriate antibiotic therapy 1

Role of Combination Therapy

• The role of combination therapy (cell wall-active agent plus aminoglycoside) for enterococcal bacteremia without endocarditis remains unresolved 1
• Some evidence suggests combination therapy with gentamicin and ampicillin may be more effective when catheters are retained 1
• Ampicillin plus high-dose ceftriaxone is an alternative combination when aminoglycosides cannot be used due to resistance or nephrotoxicity concerns 1

Evaluation for Endocarditis

• Transesophageal echocardiography (TEE) should be performed if the patient has:
  • Signs and symptoms suggesting endocarditis (new murmur, embolic phenomena)
  • Prolonged bacteremia or fever despite appropriate antimicrobial therapy (>72 hours)
  • Radiographic evidence of septic pulmonary emboli
  • Prosthetic valve or other endovascular foreign bodies 1, 6
• Endocarditis is more common with community-acquired enterococcal bacteremia than with hospital-acquired bacteremia 6

Special Considerations

• Empiric anti-enterococcal therapy is recommended for healthcare-associated infections, particularly in:
  • Postoperative infections
  • Patients who have previously received cephalosporins
  • Immunocompromised patients
  • Patients with valvular heart disease 1, 5
• Enterococcal bacteremia that persists for >4 days has been independently associated with increased mortality 1
• Amoxicillin use as documented therapy is associated with better outcomes compared to other antibiotics 2

Common Pitfalls to Avoid

• Failing to recognize enterococci as a cause of bacteremia in patients receiving cephalosporins (enterococci are intrinsically resistant to cephalosporins) 7, 8
• Inadequate treatment duration, especially in cases with endovascular infection 1, 6
• Failure to remove infected catheters when indicated 1
• Not performing TEE when indicated, potentially missing endocarditis 1
• Delayed recognition of vancomycin-resistant enterococci, which requires alternative antimicrobial therapy 1, 3