Domain Bacteria Woese et al. 1990
   Phylum Proteobacteria Garrity and Holt 2001 see Phylum Proteobacteria Garrity et al. 2005
     Class "Gammaproteobacteria" nom. inval. see Class Gammaproteobacteria Garrity et al. 2005
       Order "Thiotrichales" see Order Thiotrichales Garrity et al. 2005
         1 Family "Thiotrichaceae" see Family Thiotrichaceae Garrity et al. 2005
         2 Family "Piscirickettsiaceae" see Family Piscirickettsiaceae Fryer and Lannan 2005
         3 Family "Francisellaceae" nom. inval. see Family Francisellaceae Sjöstedt 2005