What are the recommended antibiotics for pediatric endocarditis?

Antibiotic Treatment for Pediatric Endocarditis

For pediatric infective endocarditis, bactericidal antibiotics should be administered intravenously for 4-6 weeks, with specific regimens determined by the causative organism and valve type (native vs. prosthetic). 1

Initial Empiric Therapy (Before Culture Results)

For Native Valve (Community-Acquired) Endocarditis:

• First-line: Ampicillin-sulbactam (200-300 mg/kg/day IV divided every 4-6h) plus gentamicin (3-6 mg/kg/day IV divided every 8h) with or without vancomycin 1
• Alternative: If high suspicion for MRSA, add vancomycin (60 mg/kg/day IV divided every 6h)

For Prosthetic Valve Endocarditis:

• First-line: Same as native valve PLUS rifampin (15-20 mg/kg/day divided every 12h) 1
• For early prosthetic valve endocarditis (≤1 year after surgery): Vancomycin plus gentamicin plus rifampin plus cefepime or ceftazidime 1

Organism-Specific Treatment

Streptococcal Endocarditis

• Highly penicillin-susceptible streptococci (MBC ≤0.1 μg/mL):

  • Penicillin G (200,000-300,000 U/kg/day IV divided every 4h) or
  • Ceftriaxone (100 mg/kg/day IV divided every 12h or 80 mg/kg/day once daily) for 4 weeks 1
  • For uncomplicated cases: 2-week regimen of penicillin or ceftriaxone plus gentamicin 1

• Relatively resistant streptococci (MBC ≥0.2 μg/mL):

  • Penicillin G or ampicillin plus gentamicin for 4 weeks (gentamicin for first 2 weeks) 1
  • Alternative: Vancomycin for penicillin-allergic patients 1

Staphylococcal Endocarditis

• Methicillin-susceptible S. aureus:

  • Oxacillin or nafcillin (200 mg/kg/day IV divided every 4-6h) ± gentamicin for 3-5 days 1
  • Alternative: Cefazolin (100 mg/kg/day IV divided every 8h) 1

• Methicillin-resistant S. aureus (MRSA):

  • Vancomycin (40 mg/kg/day IV divided every 8-12h) 1
  • Alternative for right-sided endocarditis: Daptomycin (6-10 mg/kg IV daily) 1

• For prosthetic valve staphylococcal endocarditis:

  • Add rifampin and gentamicin (for first 2 weeks) to the above regimens 1, 2

Enterococcal Endocarditis

• First-line: Ampicillin (200-300 mg/kg/day IV divided every 4-6h) plus gentamicin (3 mg/kg/day IV in 1 dose) for 6 weeks 1
• Alternative: Vancomycin plus gentamicin for 6 weeks 1
• For aminoglycoside-resistant enterococci: Ampicillin plus ceftriaxone 1

HACEK Group Organisms

• First-line: Ceftriaxone or cefotaxime or ampicillin-sulbactam 1
• Alternative: Ampicillin (for susceptible organisms) plus aminoglycoside 1

Duration of Therapy

• Native valve endocarditis: At least 4 weeks 1
• Prosthetic valve endocarditis: At least 6 weeks 1
• Staphylococcal endocarditis: 4-6 weeks 1, 2
• Uncomplicated right-sided endocarditis: May consider 2 weeks 2

Important Considerations

Monitoring

• Blood cultures should be obtained before starting antibiotics when possible 1
• Weekly monitoring of renal function and aminoglycoside levels is essential 3
• For gentamicin: Target peak 3-4 μg/mL, trough <1 μg/mL 3
• For vancomycin: Target trough 10-15 μg/mL 3

Pitfalls to Avoid

1. Using bacteriostatic instead of bactericidal antibiotics 1
2. Inadequate treatment duration 3
3. Monotherapy for enterococcal or prosthetic valve endocarditis 1
4. Failure to monitor for drug toxicity, especially with aminoglycosides 3
5. Intramuscular administration in children (use IV route) 1

Outpatient Therapy

• May be considered after initial inpatient treatment if:
  • Patient is hemodynamically stable
  • Afebrile with negative blood cultures
  • Not at high risk for complications
  • Home health monitoring available 1

Special Situations

• Fungal endocarditis: Surgical resection plus amphotericin B with or without flucytosine 1
• Culture-negative endocarditis: Empiric therapy as above for at least 4-6 weeks 1

Remember that bactericidal antibiotics administered intravenously for a prolonged course (4-6 weeks) remain the cornerstone of treatment for pediatric endocarditis, with specific regimens tailored to the causative organism and valve type.