FIG. 7.
VAN-allograft resists S. aureus colonization. Control or VAN-allograft were challenged with S. aureus (Ci = 104 cfu) for 6 h and adherent bacteria were observed using the Live/Dead assay. (a) Abundant viable (green) and some dead (yellow) bacteria were detected on control samples that uniformly covered the bone surface. (a, insert) Bacteria are also seen organizing in clusters producing areas of Live/Dead (Syto9 and Propidium Iodide) stain uptake that may mark the initiation of biofilm formation. (b–d) In sharp contrast, few, if any, dispersed bacteria were present on VAN-allograft from three different synthetic batches. VAN-allograft consistently appeared devoid of bacterial colonization and only exhibited a uniform yellow appearance produced from the natural fluorescence of the bone surface itself. (e) Adherent bacteria were released from the surface of bone by sonication and quantified by serial dilution and plating. VAN-allograft was able to resist colonization and significantly reduced the bacterial load on bone grafts by > 90%. *p < 0.05. Scale bars: (a–d) 200 μm (a, insert) 50 μm.