Fig. 3

Cortical allograft histology. a All images taken at ×200. Hematoxylin and eosin stain. a1–a4 Inoculated with 1 × 10² CFU S. aureus. a5–a8 Sterile control. a1 POD 4, acute inflammatory cells, no capsule; a2 POD 18, thick inflammatory capsule and evidence of neovascularization in cortical bone; a3 POD 35, thick inflammatory capsule and evidence of neovascularization in cortical bone; a4 POD 56, neovascular formation within thick capsule and extensive inflammatory reaction, a5 sterile POD 4, acute inflammatory cells, no capsule; a6 sterile POD 18; a7 sterile POD 35, thin inflammatory capsule, no evidence of bacteria, and a multinucleated giant cell with resorption pit; a8 sterile POD 56, thin inflammatory capsule, no evidence of bacteria. Note in particular the increased cellularity and inflammatory presence in the infected specimens compared to the sterile specimens. * = bone, + = capsule, white arrow = inflammatory cells, blue arrowhead = cocci bacteria. b Hematoxylin and eosin stain. Inoculated with 1 × 10² CFU S. aureus. b1 ×400, bacterial cocci within haversian canal. b2 POD 56, ×1 000, inset. Bacterial cocci and inflammatory cells within haversian canal. Note in particular the presence of both cocci bacteria and inflammatory cells co-existing in the same haversian canal space. * = bone. White arrow = inflammatory cells. Blue arrowhead = cocci bacteria