Polymerase chain reaction and synthetic DNA probes: a means of distinguishing the causative agents of syphilis and yaws?

Synthetic DNA probes specific for either the tpf-1 gene of Treponema pallidum subsp. pallidum Nichols or the tyf-1 gene of Treponema pallidum subsp. pertenue CDC 2575 were used for hybridization with in vitro-amplified chromosomal DNAs of 10 different Treponema isolates. tpf-1 and tyf-1 differ only in one nucleotide at residue 123, and three of four syphilis strains were of the Nichols type, whereas five of six yaws strains were of the CDC 2575 type, indicating that the nucleotide at position 123 of the tpf-1 or tyf-1 gene is not a definitive trait for either T. pallidum subspecies.