TREPONEMA MEDIUM SP-NOV, ISOLATED FROM HUMAN SUBGINGIVAL DENTAL PLAQUE

A new Treponema species, for which we propose the name Treponema mediu m, was isolated from subgingival plaque from an adult with periodontal disease. The morphological characteristics, differential biochemical characteristics, and protein profiles on sodium dodecyl sulfate-polyac rylamide gel electrophoresis gels of this organism are described. The guanine-plus-cytosine content of the DNA of T. medium is 51 mol%. The levels of DNA-DNA relatedness of the new species to other Treponema sp ecies, including Treponema denticola, Treponema vincentii, Treponema s ocranskii, Treponema pallidum, and Treponema phagedenis, are less than 30%. A phylogenetic analysis based on 16S rRNA sequences distinguishe d the new Treponema strain from strains belonging to previously descri bed Treponema species. The type strain of T. medium is strain G7201.