Box plot of IgG titers among patient sera against Bbp (A), alpha-toxin (B), and teichoic acid (C). Sera were from patients with diabetic foot osteomyelitis (DfOM) and soft tissue infections (ST) with S. aureus. Cutoff levels were set at +2 SD above the mean titer value in healthy controls for each antigen and are indicated by horizontal lines. Mean values are indicated by ×. *, P < 0.0001; **, P = 0.005, both analyzed by the Mann-Whitney test.