Characterization of Staphylococcus aureus strains in a rabbit model of osseointegrated pin infections.

Abstract

Staphylococcus aureus is a common infecting agent of many surgical sites. As a commensal organism to humans and rabbits, the infection process may occur due to native or exogenous S. aureus. We applied exogenous S. aureus ATCC 49230 once weekly to the surgical site of an osseointegrated pin in 20 New Zealand white rabbits. Clinical signs of infection resulted in euthanasia and at necropsy samples were collected from putatively infected sites. The predominant organism cultured was S. aureus. We observed various beta-hemolysis patterns of S. aureus on culture media and used pulsed field gel electrophoresis (PFGE) to determine whether there were distinct strains of S. aureus collected from various sites of the rabbits. On the basis of PFGE results, we found that the exogenous S. aureus ATCC 49230 was not the S. aureus cultured during necropsy, but that S. aureus native to the rabbits was in fact the infecting agent. We conclude that this rabbit model for S. aureus infection, which has not been described previously, may contribute to understanding the pathogenesis of S. aureus infections in future studies with simulated osseointegrated pin infections secondary to S. aureus.