Some species cannot be cultivated on artificial media. Glucose in a serum containing medium is required by some. The genus Treponema is the type genus. The other genus is Borrelia . There are currently many species recognized within this genus with T. denticola, T. hyodysenteriae, T. innocens, T. pallidum, T. pectinovorum, T. phagedensis, T. socranskii and T. vuncentii .
Many strains can cause human infection.
They tend to be associated with the oral, genital or intestinal tracts of humans or animals. On artificial media they are either strict anaerobes or microaerophilic. Some species need serum for growth. A variety of nutritional requirements are necessary for many species. Many form acid from sugars such as glucose, fructose and other carbohydrates.