Figure 2

Mice intravenously infected with S. aureus develop arthrosynovitis and osteomyelitis, which evolve from an acute to a chronic state.

(A) Histopathological analysis of the knees of infected mice. The knees from 4 to 6 animals/time point from 3 independent experiments were scored for severity of the lesions (Severity) and for progression of the infection (stage) both as to bones and joints analysis and mean +/− SEM were shown. (B) Representative hematoxilin-eosin-stained slide for 1 animal out of 4 to 6 at each time point. Time 0 is representative of naïve mice. Legend: F = femur, T = tibia, * = bone destruction/abscesses, # = fibroplasia/collagenous tissue, arrows = details of inflammatory cell accumulations. Scale bar: days 0, 3, 7, 200 μm; days 14, 30, 90, 1 mm; (C) Immunohistochemical staining of an abscess (Absc.) from an infected bone. S. aureus (SA, red specific staining, blue counterstaining) and neutrophils (N, blue specific staining, red counterstaining) were stained and a negative control (CTL) sample is shown in the third panel. Scale bar: 100 μm.