2013 Volume 56 Issue 6 Pages 507-515
Purpose: Prevotella intermedia, a gram negative black-pigmented anaerobic rod, is known as an initial colonizer on the tooth surface. Some clinical isolates of this organism produce mannose-rich exopolysaccharides (EPS) and form biofilms that contribute to its pathogenicity. Methods: In order to see whether this organism has the capacity to form single-species biofilm on titanium dental implants, the behaviors of three different strains of P. intermedia (strains 17, 17-2 and ATCC 25611) on titanium discs and on titanium implant fixtures vertically placed in bacterial cultures were observed by means of scanning electron microscopy. In addition, inhibitory effects of protein inhibitors such as erythromycin (EM), clarithromycin (CAM), streptomycin (SM) and tetracycline (TC) at 1/2 MIC on P. intermedia biofilm on the implant fixture were examined. Results: Both ATCC 25611 and, to a lesser extent, strain 17 adhered to the titanium disc. Although strain 17 secreted a large number of extracellular matrices on the discs, ATCC 25611 did not. Although ATCC 25611 formed microcolonies on titanium fixtures, the other two strains did not. When the fixture in culture medium was inoculated with a mixed culture of ATCC 25611 and strain 17, three-dimensional biofilm structures with a dense meshwork were constructed. The biofilm formation on the titanium fixture was reduced by the protein inhibitors. The effects of macrolides (EM and CAM) were relatively stronger than those of SM and TC. Conclusion: These results suggest that P. intermedia can form single-species biofilm on titanium dental implants when adhesive cells and cells spontaneously producing an extracellular matrix react with each other.
