Clinical utility of daptomycin in infective endocarditis caused by Gram-positive cocci

Gram-positive bacteria account for >80% of all cases of endocarditis. Currently, staphylococci are the leading cause of endocarditis worldwide. Daptomycin is the drug of choice for empirical antibiotic therapy of staphylococcal endocarditis due to its optimal activity both against meticillin-susceptible Staphylococcus aureus and meticillin-resistant S. aureus (MRSA) strains. Daptomycin has not been proven to be superior to vancomycin in the treatment of MRSA endocarditis. However, daptomycin should be considered the drug of choice for the treatment of MRSA endocarditis caused by strains with a vancomycin minimum inhibitory concentration (MIC) of 2μg/mL, for heterogeneous vancomycin-intermediate S. aureus (hVISA) phenotypes and for glycopeptide-intermediate S. aureus (GISA) strains. Daptomycin is the drug of choice for rescue therapy in cases of MRSA endocarditis in which vancomycin has failed. The appropriate dose of daptomycin has not yet been established; however, for treatment of left-sided endocarditis the dose of daptomycin should be higher than the recommended dose of 6mg/kg/day. Combination antibiotic therapy with daptomycin (e.g. combined with fosfomycin) is a promising treatment for MRSA endocarditis and warrants further investigation. In vivo studies show that daptomycin is superior to vancomycin in the treatment of meticillin-resistant coagulase-negative staphylococci experimental endocarditis, although clinical data are required. Daptomycin could represent an efficacious treatment for vancomycin-resistant Enterococcus faecium endocarditis. Finally, the pharmacokinetic profile of daptomycin makes it an excellent drug for outpatient parenteral antimicrobial therapy.