What is the treatment for endocarditis?

Treatment of Infective Endocarditis

The treatment of infective endocarditis requires a prolonged course (4-6 weeks) of bactericidal antibiotics tailored to the causative organism, with consideration for surgical intervention in approximately 50% of cases. 1

Diagnostic Approach Before Treatment

• Obtain three sets of blood cultures at 30-minute intervals before initiating antibiotics to maximize pathogen identification 1, 2
• Perform echocardiography promptly in all suspected cases; transesophageal echocardiography (TEE) is more sensitive for detecting complications like aortic root abscesses 3
• For pediatric patients, transthoracic echocardiography (TTE) has high sensitivity (up to 97%), but TEE is recommended for those >10 years of age weighing >60 kg 3

Antimicrobial Therapy Principles

• Use bactericidal rather than bacteriostatic antibiotics whenever possible 3
• Administer antibiotics intravenously to ensure complete bioavailability and high serum concentrations 1
• Treatment duration depends on the causative organism and whether native or prosthetic valve is involved 3, 1

Organism-Specific Treatment

Streptococcal Endocarditis

• For penicillin-susceptible streptococci (native valve): Penicillin G or ceftriaxone for 4 weeks 1, 4
• For penicillin-allergic patients: Vancomycin for 4 weeks 1, 5
• For prosthetic valve streptococcal endocarditis: Extend treatment to 6 weeks 3

Staphylococcal Endocarditis

• For methicillin-susceptible S. aureus (native valve): Nafcillin, oxacillin, or cefazolin for 4-6 weeks 1, 6
• For methicillin-resistant S. aureus: Vancomycin for 6 weeks 1, 5
• For prosthetic valve staphylococcal endocarditis: Add rifampin throughout treatment and gentamicin for first 2 weeks, with total duration of at least 6 weeks 3, 6, 7

Enterococcal Endocarditis

• Combination therapy with penicillin/ampicillin plus gentamicin for 4-6 weeks 1, 8
• For vancomycin-treated enterococcal endocarditis: Extend treatment to 6 weeks 3
• Aminoglycoside duration can be limited to 2 weeks to reduce toxicity while maintaining efficacy 7, 8

HACEK Organisms

• Ceftriaxone for 4 weeks in native valve endocarditis and 6 weeks in prosthetic valve endocarditis 1

Non-HACEK Gram-Negative Bacteria

• Early surgery plus long-term therapy (at least 6 weeks) with bactericidal combinations of beta-lactams and aminoglycosides 3
• Consider adding quinolones or cotrimoxazole in some cases 3

Fungal Endocarditis

• Combined antifungal therapy and surgical valve replacement due to high mortality (>50%) 3

Blood Culture-Negative Infective Endocarditis

• Consult with infectious disease specialist from the Endocarditis Team 3
• Treatment depends on suspected pathogen (see table below for specific regimens) 3

Empiric Treatment

• Start empiric therapy promptly after blood cultures are drawn, especially in severely ill patients 1, 2
• For native valve community-acquired infection: Ampicillin + (flu)cloxacillin/oxacillin + gentamicin 9
• For penicillin-allergic patients: Vancomycin + gentamicin 9
• For prosthetic valve or healthcare-associated infection: Vancomycin + gentamicin + rifampin 2

Duration of Therapy

• Native valve highly susceptible streptococci: 4 weeks 3
• Native valve staphylococci (susceptible to oxacillin): 4-6 weeks 3
• Native valve staphylococci (resistant to oxacillin): 6 weeks 3
• Prosthetic valve staphylococci: At least 6 weeks 3
• Enterococcal endocarditis: 4-6 weeks 3
• HACEK endocarditis: 4 weeks for native valve, 6 weeks for prosthetic valve 3, 1

Surgical Considerations

• Early consultation with cardiac surgery is recommended 1
• Main indications for surgery include:
  • Heart failure due to valve dysfunction 1
  • Uncontrolled infection (abscess, false aneurysm, fistula, enlarging vegetation) 1
  • Prevention of systemic embolism 1
  • Fungal or multiresistant organism infections 1
  • Persistent positive blood cultures despite appropriate antibiotic therapy 1

Monitoring During Treatment

• Repeat blood cultures until sterile to assess treatment adequacy 9
• For patients receiving vancomycin and aminoglycosides, monitor drug levels and renal function weekly 9
• Repeat echocardiography if there is suspicion of new complications 2

Special Considerations

• Outpatient parenteral antibiotic therapy may be considered for stable patients after initial hospitalization 3
• Management by a multidisciplinary "Endocarditis Team" is recommended for complex cases 1
• For persistent or relapsing S. aureus bacteremia/endocarditis, obtain repeat blood cultures and consider surgical intervention 10