The genome of Treponema pallidum: new light on the agent of syphilis.

Treponema pallidum subsp, pallidum, the causative agent of the sexually transmitted disease syphilis, is a fastidious, microaerophilic obligate parasite of humans. This bacterium is one of the few prominent infectious agents that has not been cultured continuously in vitro and consequently relatively little is known about its virulence mechanisms at the molecular level. T. pallidum therefore represented an attractive candidate for genomic sequencing. The complete genome sequence of T. pallidum has now been completed and comprises 1,138,006 base pairs containing 1041 predicted protein coding sequences. An important goal of this project is to identify possible virulence factors. Analysis of the genome indicates a number of potential virulence factors including a family of 12 proteins related to the Msp protein of Treponema denticola, a number of putative hemolysins, as well as several other classes of proteins of interest. The results of this analysis are reviewed in this article and indicate the value of whole genome sequences for rapidly advancing knowledge of infectious agents.