Comparative evaluation of daptomycin (LY146032) and vancomycin in the treatment of experimental methicillin-resistant Staphylococcus aureus osteomyelitis in rabbits.

A rabbit model for methicillin-resistant Staphylococcus aureus (MRSA) osteomyelitis was used to compare treatment with daptomycin, a new peptolide, and vancomycin. Daptomycin (4 mg/kg) and vancomycin (40 mg/kg) were injected subcutaneously every 12 and 6 h, respectively. After treatment, MRSA was found in bone cultures from 18 of 18 control rabbits, 10 of 17 animals treated with daptomycin, and 11 of 18 animals treated with vancomycin. Drug concentrations were measured in serum, uninfected bone, and infected bone 1 h after daptomycin or vancomycin was injected in a group of rabbits that had been infected for 3 to 4 weeks. Vancomycin was present at the highest concentrations in infected and uninfected bone. The results of this study suggest that daptomycin was similar to vancomycin in the eradication of MRSA from infected bone in an experimental model of osteomyelitis.