The effects of different treatment modalities on the prevalence and the severity of septic arthritis. (a) The prevalence and (b) the severity of septic arthritis in NMRI mice (n = 19–30) on days 3 and 10 following intravenous infection with S. aureus strain LS-1 were evaluated. To evaluate the severity of arthritis, a system of clinical scoring (arthritic index) was employed, where macroscopic inspection yielded a score of 0 to 3 points for each limb. The total index was calculated by adding the individual limb scores for each animal tested. Results are expressed as the mean ± SEM. CLOX, cloxacillin; PBN, phenyl-N-tert-butyl nitrone.