prokaryotes - bacteria see Domain Bacteria Woese et al. 1990
   Domain "Bacteria" Woese et al. 1990
     Phylum "Proteobacteria" Garrity et al. 2005 see Superphylum Proteobacteria Craig et al. 2010
       Class Alphaproteobacteria Garrity et al. 2006
         Order Rhizobiales Kuykendall 2006
           Family Bartonellaceae Gieszczykiewicz 1939 (Approved Lists 1980)
             Genus Grahamella (ex Brumpt 1911) Ristic and Kreier 1984 see Genus Bartonella Strong et al. 1915 (Approved Lists 1980)