High Potential of Bacterial Adhesion on Block Bone Graft Materials

Bone graft infections represent a challenge in daily clinics, resulting in increased patient discomfort and graft removal. The aim of this study was to investigate the initial adhesion of five representative pathogens on three different block bone graft materials (xenogeneic, alloplastic and allogeneic) and to assess if chlorhexidine (CHX) can effectively control the initial bacterial adhesion. Three different block bone grafting materials (Tutobone (R), Endobon (R) and human spongiosa) were incubated with Escherichia coli, Staphylococcus aureus, Streptococcus mutans, Enterococcus faecalis and Pseudomonas aeruginosa in the presence or absence of 0.2% CHX solution. Bacterial adhesion was assessed by the direct counting of the colony-forming units (CFUs) and visualized by scanning electron microscopy (SEM). Overall, the selected bacterial species adhered successfully to all tested bone replacement scaffolds, which showed similar bacterial counts. The lg CFU values ranged from 5.29 +/- 0.14 to 5.48 +/- 0.72 for E. coli, from 4.37 +/- 0.62 to 5.02 +/- 0.48 for S. aureus, from 4.92 +/- 0.34 to 4.95 +/- 0.21 for S. mutans, from 4.97 +/- 0.40 to 5.22 +/- 0.13 for E. faecalis and from 4.23 +/- 0.54 to 4.58 +/- 0.26 for P. aeruginosa. CHX did not interfere with initial microbial adhesion, and yet it killed all adhered bacterial cells. Thus, CHX can be used to prevent subsequent biofilm infections.