Treponema pallidum
Treponema pallidum is a thin, spiral-shaped bacterium that causes syphilis and, in other subspecies, yaws and endemic syphilis.
Spirochete: A slender, helical bacterium that moves using internal flagella beneath its outer membrane. T. pallidum belongs to this bacterial group and uses its internal flagella for corkscrew-like movement.
Syphilis: A sexually transmitted infection caused chiefly by Treponema pallidum subsp. pallidum. This is the principal disease caused by the bacterium.
Fritz Schaudinn: A German zoologist who, with Erich Hoffmann, reported the syphilis spirochete in 1905. His microscopy work helped identify the organism as the cause of syphilis.
Bacterial cell envelope: The layered boundary surrounding a bacterial cell, including its membrane and, in many species, a cell wall. T. pallidum’s atypical envelope helps explain its fragility and unusual staining behavior.
Borrelia burgdorferi: A spirochete bacterium that causes Lyme disease. It is another medically important spirochete, but causes a different disease and is transmitted by ticks.
Endoflagellum: A flagellum located within the periplasmic space, between a bacterium’s cell cylinder and outer membrane. Its periplasmic flagella propel T. pallidum through viscous tissues.
Bejel: A nonvenereal treponemal infection caused by Treponema pallidum subsp. endemicum, often spread through close contact. It is endemic syphilis, one of the diseases caused by another T. pallidum subspecies.
Erich Hoffmann: A German dermatologist who, with Fritz Schaudinn, reported the syphilis spirochete in 1905. He collaborated in the landmark identification of T. pallidum in lesion tissue.
Peptidoglycan: A mesh-like polymer of sugars and peptides that provides structural strength to most bacterial cell walls. T. pallidum has a thin peptidoglycan layer beneath its outer membrane.
Leptospira interrogans: A spirochete bacterium that causes leptospirosis, often after exposure to animal urine-contaminated water or soil. Its spiral form resembles treponemes, but its ecology and disease differ.