ROLE OF STAPHYLOCOCCUS-AUREUS SURFACE ADHESINS IN ORTHOPEDIC DEVICE INFECTIONS - ARE RESULTS MODEL-DEPENDENT

Bacterial colonisation of prosthetic material can lead to clinical inf ection or implant failure, or both, often requiring removal of the dev ice. Adherence of Staphylococcus aureus to bioprosthetic materials is mediated by adhesins belonging to the MSCRAMM (microbial surface compo nents recognising adhesive matrix molecules) family of microbial cell surface proteins. The objective of this study was to compare the virul ence of a mutant strain of S. aureus Newman that possesses all three f ibrinogen-, fibronectin- and collagen-binding MSCRAMMs (MSCRAMM-positi ve strain) with that of a mutant strain that lacks all three types of MSCRAMMs (MSCRAMM-negative strain) in a rabbit model of orthopaedic de vice-related infection. After a hole was drilled into the knee joint o f each animal, a group of 10 rabbits was inoculated with the MSCRAMM-p ositive strain and another group of 10 rabbits received the MSCRAMM-ne gative strain. A stainless steel screw was then placed into the drille d hole. Two weeks later, the rabbits were killed and serum samples, bo ne tissue and implants were harvested for bacteriological and histopat hological evaluation. No significant difference in infection rates was demonstrated between the two groups. The ability to delineate the rol e of S. aureus surface adhesins in causing orthopaedic device-related infection could be model-dependent.