Organized spirochetal behavior in human subgingival plaques - A virulence factor in periodontal infections?

The organization and behavior of spirochetes in human subgingival plaques was studied with phase-contrast microscopy. Wet-mounts of non-dispersed subgingival microbial specimens from deep pockets of 10 persons with untreated adult periodontitis revealed "brush formations" with outer coatings of closely-massed spirochetes exhibiting synchronized motility. Monolayers of closely-packed spirochetes co-aggregated with "brush formation" monofilaments were obtained by using mineral oil as a mounting medium for wet-mount preparations. Spirochetes were observed to produce collectively coordinated metachronal wave patterns with their cell movements along the outer surfaces of the "brush formation" monofilaments, rather than flexing independently and at random. Organized spirochetal activity in subgingival plaques may serve as a virulence factor contributing to the periodontopathic potential of spirochetes and/or other microbial species.