Animal Models of Implant Related Infection

Increasing antibiotic resistance amongst bacteria within the hospital and community environments will ensure that musculoskeletal infection continues to pose a major challenge to clinicians. At the same time, it is clear that current infection rates and treatment algorithms could benefit from new technologies such as antimicrobial activated coatings. Safe and expedient implementation of this technology relies on well-designed and clinically relevant in vivo simulation using animal models.

Many animal models of musculoskeletal infection have been described in the literature; however, there remains a dearth of fully standardised or universally accepted reference models hindering advancement in the field. The design variables involved in creating a model are manifold and inevitably demand compromise. An inherent limitation of animal models is the difficulty in extrapolating results not only to humans, but also to other animals or to the same model in another laboratory.

In the orthopaedic and trauma field, standardisation and refinement of fixation methods would also improve existing models. Rabbits, rats and mice, for example have been frequently used in the field but the nature of implant or fixation and the anatomical location used vary. Stable, repeatable fixation systems, which mirror clinical practice and reliably heal fractures without complication, should be the starting point for clinically relevant research and development into anti-infective strategies in the field.

Recent advances in some of these areas have been made and the burgeoning availability of tools for longitudinal in vivo monitoring of infection via the use of bioluminescent bacteria is another exciting development in the field. These refinements and others should enable the creation of robust, controlled and consistent models, which allow strong scientific conclusions with a minimum of harm to animals.  [...]