Domain Bacteria Woese et al. 1990
   Phylum Proteobacteria Garrity and Holt 2001 see Phylum Proteobacteria Garrity et al. 2005
     Class "Epsilonproteobacteria" nom. inval. see Class Epsilonproteobacteria Garrity et al. 2006
       1 Order "Campylobacterales" nom. inval. see Order Campylobacterales Garrity et al. 2006