[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 Deltaproteobacteria Kuever et al. 2006
         Order Desulfovibrionales Kuever et al. 2006
           Family Desulfovibrionaceae Kuever et al. 2006
             Genus Lawsonia McOrist et al. 1995
               1 Lawsonia intracellularis McOrist et al. 1995