Treponema pallidum is a species of spirochaete bacterium with subspecies that cause treponemal diseases such as syphilis, bejel, pinta and yaws. It is not seen on a Gram stained smear because the organism is too thin. Alternative Names: p, p47 Treponema Pallidum-15 protein, p17, p47 Treponema Pallidum 15, p, p, p47 Treponema Pallidum, p, p17, p47 Treponema Pallidum 15 protein, p47 Treponema Pallidum-15, p15, p17, p17, p17, p17, p15, p47 Treponema Pallidum Antigen