Locomotory characteristics of Treponema denticola.

Locomotion of pathogenic spirochetes has been suggested as a virulence factor in their pathogenesis. Little is known of the locomotory characteristics of oral anaerobic spirochetes. We have determined the optimal conditions for motility of seven strains of Treponema denticola in menstrua of different viscosities. The viscosity for optimum motility for all strains was found to be 9.57 centipoises at 25 degrees C. Under these conditions the average speeds for each strain was computed from the motility tracks as recorded by timed exposures under dark-field microscopy. Differences in speeds were found between the various strains. In addition, we have determined the "persistence" (direct distance/actual pathlength travelled) of cell movement of each strain. Interstrain differences were also noted. These locomotory characteristics contribute to the locomotory phenotypes of the various strains and therefore may aid in their characterization and provide an insight into locomotion as a virulence factor in periodontitis.