[Treatment of multiresistant Gram positive endocarditis].

Epidemiology of infectious endocarditis has changed in last decades, endocarditis associated to hospital practices, sustained by multiresistant pathogens being highly increased. In particular, methicillin-resistant staphylococci (MRSA), almost resistant to a number of other antimicrobial classes, often exhibit a reduced susceptibility to vancomycin (h-VISA) with MICs' values more e than 1 mg/l, leading to suppose a reduced therapeutic efficacy of this drug. Thirty-one percent of MRSA strains in the ICE study, which prospectively collected more than 5000 endocarditis, were h-VISA. Daptomycin shows a rapid bactericidal activity against both methicillin-susceptible staphylococcci (MSSA) and MRSA, included those strains with reduced susceptibility to vancomycin. Daptomycin shows a good therapeutic efficacy in staphylococcal endocarditis: MRSA 71%, MSSA 75%. These data suggest the use of daptomycin as initial therapy for treatment of staphylococcal endocarditis, independently from methcillin susceptibility. Some experimental data showed that daptomycin efficacy can diminish, if it is used as a rescue therapy after vancomycin failure. The thickness of bacterial cell-wall recognized in h-VISA strains can represent a physical and electrical barrier to reach both the vancomycin and daptomycin target site. However, the reduced efficacy of daptomycin following vancomycin exposure is an extremely rare event in the clinical practice. It is preferrable to use daptomycin as first line therapy, at a proper dosage. As far as endocarditis is concerned, recent data proved the excellent daptomycin tolerability, with dosages up to 8-10 mg/kg/die. During the treatment, CPK values must be always monitored. For endocarditis sustained by vancomycin-resistant enterococci, therapeutic choices are based on linezolid or ampicillin-ceftriaxone combination therapy. Daptomycin alone, or in association with gentamycin and rifampin, can represent a promising therapeutic alternative.