Formal description of Treponema pallidum subsp. pallidum, comb. nov., Treponema pallidum subsp. pertenue, comb. nov., Treponema pallidum subsp. endemicum, subsp. nov. and emended description of Treponema pallidum.

This article represents the valid publication of the names of three subspecies of Treponema pallidum. These subspecies were first described by Robert M. Smibert in 1984 and correspond with organisms that cause syphilis (subsp. pallidum), yaws (subsp. pertenue) and bejel (subsp. endemicum) in humans. The subspecies nomenclature has been widely used in the literature since that time but has not been validly published due in part to the availability of only limited genetic information. The designation of these subspecies is now supported by a large number of genomic sequences indicating a clear separation of these three closely related yet genetically distinct groups, as demonstrated in this study by phylogenetic analysis of a representative group of strains from each subspecies and the closely related lagomorph pathogen Treponema paraluiscuniculi. Subspecies-specific regions were also identified by genomic comparisons to provide an additional means of distinguishing the T. pallidum subspecies and T. paraluiscuniculi without complete genomic sequencing. Finally, the GauthierT (=BEI Resources NR-60826T=DSM 120346T) and Bosnia AT (=BEI Resources NR-60824T=DSM 120347T) strains are herein designated as the type strains of T. pallidum subsp. pertenue and T. pallidum subsp. endemicum, respectively, whereas NicholsT (=BEI Resources NR-59701T=DSM 117211T) and SS14 (=BEI Resources NR-60825=DSM 120345) represent type and reference strains of T. pallidum subsp. pallidum, respectively. Overall, this article corroborates the many prior reports that support the formal establishment of the three T. pallidum subspecies and provides additional guidelines for their distinction.