The study evaluates the efficacy and safety of fosfomycin and imipenem for the treatment of methicillin-resistant staphyloccocus aureus infective endocarditis in comparison to vancomycin, the standard therapy.

Inclusion Criteria:

• Suspected methicillin-resistant staphyloccocus aureus infective endocarditis on a native valve, prosthetic valve or pacemakers´s electrode or defibrillators with definitive or probable diagnosis by the modified Duke criteria (Li J, et al. Clin Infect Dis. 2000).
• Patients over 18 years.

Exclusion Criteria:

• Patients who did not sign informed consent.
• Patients with active consumption intravenous drug.
• Patients with emergent surgery criteria (<72 hours).
• Patients or cardiogenic shock.
• Patients with antibiotic active against MRSA over 72 hours or they may need another antibiotic active against MRSA than those in the study.
• Patients with chronic renal failure on hemodialysis who received empirical treatment with vancomycin as a single dose and have a valley ≥ 15 mcg / mL on the third day.
• Patients with MRSA strains resistant to fosfomycin (MIC> 64 mg / L) (<10%) or vancomycin (MIC> 2 mg / L) or with an MIC to vancomycin of 2 mg / L.
• Patients with any formal contraindication to be treated with study drugs
• Patients treated with any investigational drug within 30 days prior to entering the study.