[organisms] see Clade Biota Wagner 2004 [Wiemann, de Queiroz, Rowe, Planavsky, Anderson, Gogarten, Turner & Gauthier 2020]
   Domain Bacteria Woese et al. 1990
     Phylum "Proteobacteria" Garrity et al. 2005 see Superphylum Proteobacteria Craig et al. 2010
       Class Epsilonproteobacteria Garrity et al. 2006
         Order Campylobacterales Garrity et al. 2006
           Family Campylobacteraceae Vandamme and De Ley 1991
             Genus Campylobacter Sebald and Véron 1963 (Approved Lists 1980)
               [Campylobacter fetus] (Smith and Taylor 1919) Sebald and Véron 1963 (Approved Lists 1980)
                 1 Campylobacter fetus subsp. fetusᵀ (Smith and Taylor 1919) Véron and Chatelain 1973 (Approved Lists 1980)
                 2 Campylobacter fetus subsp. venerealis (Florent 1959) Véron and Chatelain 1973 (Approved Lists 1980)