What is the treatment for endocarditis (infection of the inner lining of the heart)?

From the Guidelines

Endocarditis treatment requires hospitalization and a prolonged course of intravenous antibiotics, typically lasting 4-6 weeks, with initial empiric therapy often including vancomycin (15-20 mg/kg IV every 12 hours) plus ceftriaxone (2g IV daily) while awaiting blood culture results. The choice of antibiotics should be tailored according to the identified causative organism, with options including penicillin G (12-18 million units IV daily) or ceftriaxone for streptococcal infections, or nafcillin/oxacillin (2g IV every 4 hours) for methicillin-sensitive Staphylococcus aureus 1.

Key Considerations

• Surgical intervention becomes necessary in about 50% of cases, particularly with heart valve damage, persistent infection despite antibiotics, large vegetations (>10mm), or recurrent emboli 1.
• Patients need regular blood tests to monitor antibiotic levels and effectiveness, and echocardiograms to assess vegetation size and valve function 1.
• Prompt treatment is crucial as endocarditis has a mortality rate of 15-30% even with appropriate therapy 1.
• Following treatment, preventive antibiotics before dental procedures may be recommended for high-risk patients, and addressing any underlying risk factors like intravenous drug use is essential for preventing recurrence 1.

Antibiotic Regimens

• For methicillin-susceptible staphylococci, a semisynthetic, β-lactamase–resistant penicillin (nafcillin or oxacillin) given intravenously for a minimum of 4 to 6 weeks is recommended 1.
• For methicillin-resistant staphylococcal endocarditis, treatment with vancomycin for a minimum of 6 weeks, with or without gentamicin for the first 3 to 5 days, is recommended except when the organism is not susceptible to vancomycin 1.
• The addition of gentamicin for the first 3 to 5 days may be considered, but it increases the likelihood of renal and otic toxicity 1.

Special Considerations

• Patients with culture-negative endocarditis should be classified into one of two groups: those who received antibiotic therapy before collection of blood cultures, and those who did not 1.
• For patients with acute clinical presentations of native valve infection, coverage for S aureus should be provided as outlined in the section on the treatment of proven staphylococcal disease 1.
• Patients with prosthetic valve infection should receive vancomycin if onset of symptoms begins within 1 year of prosthetic valve placement to provide coverage of oxacillin-resistant staphylococci 1.

From the FDA Drug Label

Vancomycin Hydrochloride for Injection, USP is effective in the treatment of staphylococcal endocarditis Vancomycin Hydrochloride for Injection, USP has been reported to be effective alone or in combination with an aminoglycoside for endocarditis caused by S. viridans or S. bovis. For endocarditis caused by enterococci (e.g., E. faecalis), vancomycin has been reported to be effective only in combination with an aminoglycoside. Vancomycin Hydrochloride for Injection, USP has been used successfully in combination with either rifampin, an aminoglycoside, or both in early-onset prosthetic valve endocarditis caused by S. epidermidis or diphtheroids.

Treatment of Endocarditis:

• Vancomycin can be used to treat staphylococcal endocarditis.
• For endocarditis caused by S. viridans or S. bovis, vancomycin can be used alone or in combination with an aminoglycoside.
• For endocarditis caused by enterococci, vancomycin should be used in combination with an aminoglycoside.
• Vancomycin can also be used in combination with rifampin, an aminoglycoside, or both for early-onset prosthetic valve endocarditis caused by S. epidermidis or diphtheroids 2.

From the Research

Treatment Strategies for Endocarditis

• The treatment of endocarditis typically involves the use of antibiotics, with the specific regimen depending on the causative microorganism and other factors 3, 4, 5, 6.
• For staphylococcal endocarditis, anti-staphylococcal penicillins or vancomycin may be used, with gentamicin and rifampin added for prosthetic-valve endocarditis 3.
• The optimal duration of antibacterial treatment is typically 4-6 weeks, depending on the type of endocarditis and the presence of a prosthetic valve 3.
• Oral switch therapy may be safe in patients who have stabilized after initial intravenous treatment 3.

Antibiotic Regimens

• Various antibiotic regimens have been compared in clinical trials, including quinolone plus standard treatment, fosfomycin plus imipenem, and vancomycin plus gentamicin 5.
• The results of these trials have been inconsistent, with some showing no significant difference in outcomes between regimens, while others have reported varying degrees of efficacy 5.
• Vancomycin-based regimens have been shown to be effective in some cases, particularly for highly penicillin-resistant viridans group streptococcal endocarditis 6.

Specific Considerations

• The use of aminoglycosides, such as gentamicin, has been reduced in recent years due to concerns about toxicity, but may still be used in certain cases 3.
• Daptomycin has been shown to be effective in some cases, but the emergence of high-level daptomycin resistance is a concern 6.
• The choice of antibiotic regimen should be individualized based on the specific characteristics of the patient and the causative microorganism 3, 4, 5, 6.