Rapid Systemic Bone Resorption during the Course ofStaphylococcus aureus–Induced Arthritis

Bacterial arthritis is the most rapidly progressing destructive joint disease in humans. To evaluate bone resorption and formation, mice were injected with Staphylococcus aureus and killed after 3 and 14 days. Both total and trabecular bone mineral density were, compared with those in uninfected controls, already significantly reduced 3 days after bacterial inoculation. Serum levels of type I collagen fragments were significantly increased and osteocalcin levels decreased in mice infected with S. aureus, compared with those in noninfected mice, 3 and 14 days after bacterial inoculation. This study shows that there is a rapid and easily measurable systemic bone resorption during S. aureus-induced arthritis.