Copper Bead Therapy in Severe Bone Infection: A Rabbit Tibial Model.

OBJECTIVE: We investigated the benefits of a local preventive therapy based on copper beads against severe bone infection using a rabbit open tibial fracture model. MATERIALS AND METHODS: Cotton mesh balls soaked in a very high concentration of Staphylococcus aureus ATCC 6538 culture were inoculated in drilled holes of the tibiae of treated and control groups. The treated group was also implanted with small copper beads simultaneously, as prevention therapy. RESULTS: Survival rate in the treated group was 67% compared with 25% in the control group (difference 40%, for a 95% confidence interval: 40%, 93.4%). The few remaining animals in the control group had bone lesions which developed into osteomyelitis, while the tibiae of treated group had clear signs of reparatory processes. Sixty days after inoculation, signs of local-only toxicity were observed in healthy tibia of a separate non-infected control group. Drawbacks of copper toxicity were weighed against the threat of septicaemia and also against prolonged use of powerful systemic antibiotic medications in severe bone contamination. CINICAL SIGNIFICANCE: It was found that the proposed therapy prevented septicaemia and the spread of infection, and it also induced reparatory processes. The findings of this study may be relevant in antisepsis of open fractures in less appropriate medical settings (such as military camps or remote locations), as well as in severe bone infections.

The influence of foreign body surface area on the outcome of chronic osteomyelitis.

Reproducible animal models of osteomyelitis close to the clinical scenario are difficult to obtain as the animals either die shortly after inoculation of bacteria or the bone cures itself of infection. Additional materials used as foreign bodies offer increased chances for localized infection due to bacterial attachment and are closer to clinical pathology. Through in vivo experimentation we investigated here the influence of surface area of a series of foreign bodies on the final outcome of the animal model, in terms of reproducibility, survival rate and time necessary for onset of chronic disease. Stainless steel Kirschner wire segments, stainless steel balls and cotton meshes were employed for this purpose. The clinical, microbiological, radiological and histological results obtained were compared with the simple case where no foreign body was used. The follow-up period was 57days. The cotton meshes, which had the highest surface area, were observed to provide the best outcome, with the lowest disease onset time interval (of 1week earlier than the others), the highest survival (of 90%) and disease reproduction rate (90%). The only clinical pattern of the mesh group rabbits was short lived inflammation while the other rabbits presented also some other clinical signs such as rhinorrheas, abscesses, rush and/or dyspnea. Moreover, this model is the most suitable for further treatment studies, as the cotton meshes could be easily removed after disease onset, without any intervention on the bone. This is important, as the treatment would address the bacteria present within the bone parts (marrow, cortex, periosteum etc.) not those forming the biofilm.