From the Guidelines
Treatment of MRSA prosthetic valve endocarditis requires aggressive antimicrobial therapy with vancomycin, rifampin, and gentamicin, and often surgical intervention, to reduce morbidity, mortality, and improve quality of life. The recommended regimen includes vancomycin (30-60 mg/kg/day IV in 2-3 doses) plus rifampin (900-1200 mg IV or orally in 2 or 3 divided doses) and gentamicin (3 mg/kg/day IV or IM in 1 or 2 doses) for the first 2 weeks, followed by continuation of vancomycin and rifampin for a total of at least 6 weeks 1.
Key Considerations
- Vancomycin trough levels should be maintained at ≥20 mg/L to ensure effective treatment 1.
- Gentamicin can be given in a single daily dose to reduce renal toxicity 1.
- Daptomycin (10 mg/kg/day IV once daily) may be used as an alternative to vancomycin, particularly in cases of vancomycin treatment failure or intolerance 1.
- Early surgical consultation is essential, as valve replacement is often necessary due to the difficulty in eradicating MRSA from prosthetic material with antibiotics alone 1.
- Surgery is particularly indicated in cases with persistent bacteremia despite appropriate antibiotics, valve dysfunction, large vegetations (>10 mm), or embolic events.
Monitoring and Follow-up
- Blood cultures should be monitored regularly to ensure clearance of bacteremia.
- Renal function and serum gentamicin concentrations should be monitored once/week (twice/week in patients with renal failure) 1.
- This aggressive approach is necessary because MRSA forms biofilms on prosthetic surfaces that protect bacteria from antibiotics and host immune responses, making eradication particularly challenging without the combination of prolonged antimicrobial therapy and often surgical intervention 1.
From the FDA Drug Label
Patients with persisting or relapsing S. aureus bacteremia/endocarditis or poor clinical response should have repeat blood cultures. If a blood culture is positive for S aureus, minimum inhibitory concentration (MIC) susceptibility testing of the isolate should be performed using a standardized procedure, and diagnostic evaluation of the patient should be performed to rule out sequestered foci of infection. Appropriate surgical intervention (e.g., debridement, removal of prosthetic devices, valve replacement surgery) and/or consideration of a change in antibacterial regimen may be required.
The treatment of MRSA prosthetic valve infection may require surgical intervention, such as removal of the prosthetic device or valve replacement surgery, in addition to antibacterial therapy with daptomycin 2. Appropriate surgical intervention may be necessary to treat the infection, especially if the patient has a poor clinical response or persisting/relapsing infection.
From the Research
Treatment Options for MRSA Prosthetic Valve Endocarditis
- Daptomycin has been shown to be effective in treating MRSA prosthetic valve endocarditis, particularly in cases where vancomycin therapy has failed 3.
- Ceftaroline, a new cephalosporin, has also been used as a salvage therapy for MRSA prosthetic valve endocarditis, with promising results 4.
- Combination therapy with rifampicin and other antibiotics, such as daptomycin or vancomycin, may also be effective in treating MRSA prosthetic valve endocarditis 5, 6.
Antibiotic Regimens
- Daptomycin monotherapy has been used to treat MRSA prosthetic valve endocarditis, with a dosage of 6 mg/kg/d 3.
- Ceftaroline has been used at high doses, given three times daily, to treat MRSA prosthetic valve endocarditis 4.
- Combination therapy with daptomycin, vancomycin, and rifampin has been used to treat recurrent MRSA bone and prosthetic joint infections, and may also be effective for MRSA prosthetic valve endocarditis 6.