Bor.rel.i.a.ce'ae. N.L. fem. n. Borrelia type genus of the family; suff. ‐aceae ending to denote a family; N.L. fem. pl. n. Borreliaceae, the family of Borrelia.
Spirochaetes / Spirochaetia / Spirochaetales / Borreliaceae
Cells are helical with regular or irregular coils, 0.2–0.3 µm in diameter and 10–40 µm in length. Cells do not have hooked ends. Motile. Inner and outer membrane with periplasmic flagella with 7–20 subterminal insertion points. Aniline‐stain‐positive. Microaerophilic. Most members of the family cultivable in complex media that includes N‐acetylglucosamine. Optimum growth between 33°C and 38°C. Diamino acid of peptidoglycan is ornithine. Lacks a lipopolysaccharide. Linear chromosome and plasmids with hairpin telomeres. The family currently accommodates the genera Borrelia and Borreliella. Members of the family are host‐associated organisms that are transmitted between vertebrate reservoirs by a hematophagous arthropod, in all but one case, a tick. Members include the agents of relapsing fever, Lyme disease, and avian spirochetosis.
DNA G + C content (mol%): 26–30.
Type genus: Borrelia Swellengrebel 1907, 562AL.