Vancomycin-loaded nano-hydroxyapatite pellets to treat MRSA-induced chronic osteomyelitis with bone defect in rabbits

To investigate nano-hydroxyapatite (nHA) pellets as carriers for vancomycin in the treatment of chronic osteomyelitis and bone defects due to methicillin-resistant Staphylococcus aureus (MRSA) strains. Chronic osteomyelitis was induced in 45 New Zealand white rabbits. After 3 weeks (chronic infection), all animals were treated with debridement. The rabbits were divided into an experimental group (the bone was filled with vancomycin-loaded nHA pellets), a control group (the bone was filled with nHA pellets alone), and a blank group. The drug release profiles were determined in vitro and in vivo. X-rays, bone specimens, and microorganism cultures were used to evaluate the efficacy of the treatments. Following a rapid initial release into the circulation, the drug concentration remained effective in the osseous and soft tissues for 12 weeks after debridement. Within 3 months, all rabbits in the experimental group recovered from osteomyelitis without a recurrence of the infection and the bone defects were partially repaired, whereas the infection and bone defects persisted in the control and blank groups. The results demonstrate that vancomycin-loaded nHA pellets successfully repair bone defects and control infection in MRSA-induced chronic osteomyelitis. In addition, nHA is an effective and safe controlled-release vancomycin carrier for chronic osteomyelitis with bone defects that is induced by MRSA.