Phenotypic and genotypic heterogeneity among cultivable pathogen-related oral spirochetes and Treponema vincentii

Recent findings challenge the assumption that pathogen-related oral spiroch etes (PROS) are related to Treponema pallidum. Treponema vincentii, grown i n OMIZ-Pat media, cross-reacted with monoclonal antibody H9-2 against T. pa llidum, and cultivable PROS had 16S rRNA gene sequences similar to those of T. vincentii (C.-B. Choi, C. Wyss, and U. B. Gobel. J. Clin, Microbiol, 34 :1922-1925, 1996). Aims of the present study were to determine whether anti gen phenotypes of oral treponemas were influenced by growth conditions and to evaluate the genetic relatedness of cultivable PROS to T. pallidum and T . vincentii, Results show that three T. pallidum monoclonal antibodies (H9- 1, H9-2, and F5) cross-reacted with whole cells from Four Treponema species grown in modified OMIZ-Pat medium, but not with treponemas grown in NOS me dium. Only H9-2 reacted in immunoblots with reduced proteins from cultivabl e PROS and T. vincentii. Three of five PROS isolates were amplified by T, v incentii-specific PCR, and one was amplified by Treponema medium-specific P CR, None were amplified by T. pallidum-specific PCR, Three of five PROS iso lates had 16S ribosomal DNA restriction fragment length polymorphism patter ns identical to that of T. vincentii, and the patterns of two isolates rese mbled that of T. medium, Arbitrarily primed-PCR profiles from whole genomic DNA were distinct among five PROS isolates and two T, vincentii strains. T hus, PROS isolates represent a heterogeneous group of treponemas that share some 16S rRNA gene sequences with T. vincentii and T. medium, but not with T. pallidum. It is proposed that the PROS nomenclature be dropped.