Domain Bacteria Woese et al. 1990
   Phylum Spirochaetes Garrity and Holt 2001
     Class "Spirochaetes" Cavalier-Smith, 2002 see Class Spirochaetes Cavalier-Smith 2002
       Order Spirochaetales Buchanan 1917 (Approved Lists 1980)
         Family Spirochaetaceae Swellengrebel 1907 (Approved Lists 1980)
           Genus Borrelia Swellengrebel 1907 (Approved Lists 1980)
           Genus Brevinema Defosse et al. 1995
           Genus Clevelandina Bermudes et al. 1988
           Genus Cristispira Gross 1910 (Approved Lists 1980)
           Genus Diplocalyx (ex Gharagozlou 1968) Bermudes et al. 1988
           Genus Hollandina (ex To et al. 1978) Bermudes et al. 1988
           Genus Pillotina (ex Hollande and Gharagozlou 1967) Bermudes et al. 1988
           Genus Treponema Schaudinn 1905 (Approved Lists 1980)
           1 Genus Spirochaeta Ehrenberg 1835 (Approved Lists 1980)