A case of osteitis due to Staphylococcus aureus and Arcanobacterium bernardiae coinfection.

Arcanobacterium bernardiae human infections remain rare. Only 2 reports are described in the literature. We report on an immunocompetent patient with a long history of chronic osteitis who developed a polymicrobial infection of the knee. The initial isolation of Staphylococcus aureus confounded the diagnosis of A. bernardiae infection, which underlines the need for extended period of incubation and subcultures of enriched liquid culture media. A. bernardiae is a new bacterium implicated in osteoarticular infections.