[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 Betaproteobacteria Garrity et al. 2006
         Order Burkholderiales Garrity et al. 2006
           Family Alcaligenaceae De Ley et al. 1986
             Genus Alcaligenes Castellani and Chalmers 1919 (Approved Lists 1980)
               [Alcaligenes faecalis] Castellani and Chalmers 1919 (Approved Lists 1980)
                 1 Alcaligenes faecalis subsp. faecalisᵀ (Castellani and Chalmers 1919) Austin et al. 1981
                 2 Alcaligenes faecalis subsp. parafaecalis Schroll et al. 2001
                 3 Alcaligenes faecalis subsp. phenolicus Rehfuss and Urban 2006