Fig. 1

Quantitative real-time bacterial burden on cortical allograft at increasing inoculums in a mouse model. a Measurement of bacterial burden using in vivo bioluminescence. S. aureus possessing the bioluminescent construct in a stable plasmid (Xen36) in four inoculums [5 × 10¹, 1 × 10², 1 × 10³, 1 × 10⁴ colony-forming units (CFU)] or no bacteria as a control were inoculated on a cortical allograft implanted into mice. Bacterial counts as measured by in vivo S. aureus bioluminescence [total flux (photons per s per cm²)sem (logarithmic scale)]. Error bars represent standard error of the mean. ^†P < 0.05 compared to sterile in the mixed effects regression model using a group-by-time interaction term. Experiment was carried out through postoperative day (POD) 56 in order to identify an end plateau to the main curve of interest, the 1 × 10² inoculum. b Cortical allograft surgery. Mouse on left inoculated with 1 × 10² CFUs S. aureus had a healed surgical wound on POD21. Mouse on right inoculated with 1 × 10³ CFUs S. aureus had wound breakdown necessitating euthanasia on POD21