Treponema pallidum

Treponema pallidum, or the pale treponema, is the agent which causes syphilis.

Characteristics of Treponema pallidum

Treponema pallidum is a Gram negative bacterium belonging to the Spirochete family, the only known host for which is human beings. The other Treponema bacteria do not cause sexually transmissible diseases (STD).

The bacterium is spiral shaped, from eight to 15 micrometers long and 0.2 micrometers in diameter. Its spiral shape allows it to propel itself by rotating around its central axis.

Treponema pallidum has a small, 1.14 million base pair genome which codes for 1,041 putative proteins.

Treponema pallidum and syphilis

In the appropriate environment (within the host) the bacterium replicates in around thirty hours.

The bacterium does not have lipopolysaccharide, the typical endotoxin found in Gram negative bacteria. In order to cause symptoms of syphilis, it produces lipoproteins which can induce the production of inflammatory factors in the host.

Treponema pallidum is transmitted sexually, although it spreads rapidly to the deep tissues and into the blood circulation.