Introduction: Antimicrobial peptides (AMP) are a novel class of antimicrobial agents effective against among others MRSA in vitro. Previously, we reported the release of AMP Dhvar-5 and hLF1-11 from different bone cements^(1,4). In this study we investigated the efficacy of calcium phosphate cement (Calcibon^®) loaded with hLF1-11 for the treatment of MRSA osteomyelitis in vivo.

Materials and Methods: Osteomyelitis was induced in 14 rabbits by MRSA, as described by Norden et al.⁽²⁾ After 3 weeks all animals were treated by a thorough local debridement and subsequent filling of the tibial cavity with Calcibon^® bone cement. Six control animals received Calcibon^® without additives and 8 animals received Calcibon^® loaded with 50 mg hLFl-11 per g cement powder. Treatment outcome was analyzed by microbiology, radiology and histology after 3 weeks follow-up.

Results: The results are shown in table 1. The number of CFU per gram of bone were significantly lower in the 50 mg hLFl-11 group (median 3.0x10³ CFU/g bone) compared to the control group (median 3.5xl0⁶ CFU/g bone).

Conclusion: This study demonstrates that hLFl-11 has the ability to cure an existing MRSA osteomyelitis in 5 out of 8 animals. The data suggest that the antimicrobial peptide, hLFl-11 in Calcibon^® is able to treat osteomyelitis in vivo.