Infected tibias were sectioned and stained with (i) Brown-Brenn Gram stain to visualize S. aureus communities in crystal violet, (ii) Alcian blue hematoxylin-orange G (ABHO) to visualize mature calcified bone in orange to red and soft tissues in pink to red for abscesses, and (iii) tartrate-resistant alkaline phosphatase (TRAP) for osteoclast activation in pink to indicate areas of osteolysis (Fig. 2A). The gene discussed is ACP5; the disease is abscess.