S. aureus isolated from patients suffering from septic arthritis and osteomyelitis specifically interacts with bone sialoprotein (BSP), a noncollagenous protein of bone and dentine extracellular matrix, mediated by Bbp (Ganss et al., 1999; Ryden et al., 1987; Tung et al., 2000). Here, IBSP is linked to bacterial arthritis.