life see Clade Biota Wagner 2004 [Wiemann, de Queiroz, Rowe, Planavsky, Anderson, Gogarten, Turner & Gauthier 2020]
   Superkingdom Prokarya see Domain Bacteria Woese et al. 1990
     Kingdom Bacteria (Cohn 1870) Cavalier-Smith 1983 - bacteria see Kingdom Bacteria Cavalier-Smith 2002
       Subkingdom Eubacteria Cavalier-Smith 1981 see Domain Bacteria Woese et al. 1990
         Division Gracilicutes Gibbons and Murray 1978 (Approved Lists 1980) see Phylum Gracilicutes
           Phylum Proteobacteria Garrity and Holt 2001 see Phylum Proteobacteria Garrity et al. 2005
             01 Genus Actinobacillus Brumpt 1910 (Approved Lists 1980)
             02 Genus Aerobacter
             03 Genus Alginobacter
             04 Genus Amoebobacter Winogradsky 1888 (Approved Lists 1980) see Genus Thiocapsa Winogradsky 1888 (Approved Lists 1980)
             05 Genus Ancalomicrobium Staley 1968 (Approved Lists 1980)
             06 Genus Bradyrhizobium Jordan 1982
             07 Genus Caedibacter (ex Preer et al. 1974) Preer and Preer 1982
             08 "Alpha Group" see Class Alphaproteobacteria Garrity et al. 2006
             09 "Beta Group" see Class Betaproteobacteria Garrity et al. 2006
             10 "Gamma Group" see Class Gammaproteobacteria Garrity et al. 2005
             11 "Delta Group" see Class Deltaproteobacteria Garrity et al. 2001 nom. ined.
             12 Genus Daptobacter
             13 Genus Calymmatobacterium Aragão and Vianna 1913 (Approved Lists 1980) see Genus Klebsiella Trevisan 1885 (Approved Lists 1980)
             14 Genus Cardiobacterium Slotnick and Dougherty 1964 (Approved Lists 1980)
             15 Genus Chloropseudomonas
             16 Genus Chromobacterium Bergonzini 1880 (Approved Lists 1980)
             17 Genus Coxiella (Philip 1943) Philip 1948 (Approved Lists 1980)
             18 Genus Desulfacinum Rees et al. 1995
             19 Genus Desulfonema Widdel 1981
             20 Genus Desulfotomaculum Campbell and Postgate 1965 (Approved Lists 1980)
             21 Genus Ferrobacillus
             22 Genus Flavobacterium Bergey et al. 1923 (Approved Lists 1980)
             23 Genus Haemophilus Winslow et al. 1917 (Approved Lists 1980)
             24 Genus Streptobacillus Levaditi et al. 1925 (Approved Lists 1980)
             25 Genus Macromonas Utermöhl and Koppe 1924 (Approved Lists 1980)
             26 Genus Methylosinus (ex Whittenbury et al. 1970) Bowman et al. 1993
             27 Genus Neorickettsia Philip et al. 1953 (Approved Lists 1980)
             28 Genus Nitrococcus Watson and Waterbury 1971 (Approved Lists 1980)
             29 Genus Nitrocystis
             30 Genus Nitrosococcus Winogradsky 1892 (Approved Lists 1980)
             31 Genus Nitrosogloea
             32 Genus Nitrosolobus Watson et al. 1971 (Approved Lists 1980) see Genus Nitrosospira Winogradsky and Winogradsky 1933 (Approved Lists 1980)
             33 Genus Nitrosospira Winogradsky and Winogradsky 1933 (Approved Lists 1980)
             34 Genus Nitrospira Watson et al. 1986
             35 Genus Oceanospirillum Hylemon et al. 1973 (Approved Lists 1980)
             36 Genus Pseudomonas Migula 1894 (Approved Lists 1980)
             37 Genus Rhodoferax Hiraishi et al. 1992
             38 Genus Rickettsia da Rocha-Lima 1916 (Approved Lists 1980)
             39 Genus Rickettsiella Philip 1956 (Approved Lists 1980)
             40 Genus Rubrivivax Willems et al. 1991
             41 Genus Thermodesulforhabditis
             42 Genus Thiobacterium (ex Janke 1924) La Riviere and Kuenen 1989
             43 "Prosthecate Bacteria" see Order Caulobacterales Henrici and Johnson 1935 (Approved Lists 1980)
             44 Genus Thiocystis Winogradsky 1888 (Approved Lists 1980)
             45 Genus Thiodictyon Winogradsky 1888 (Approved Lists 1980)
             46 Genus Thiomicrospira Kuenen and Veldkamp 1972 (Approved Lists 1980)
             47 Genus Thiopedia Winogradsky 1888 (Approved Lists 1980)
             48 Genus Thiosarcina
             49 Genus Thiospira Visloukh 1914 (Approved Lists 1980)
             50 Genus Thiothece
             51 Genus Thiovulum Hinze 1913 (Approved Lists 1980)
             52 "Acetic Acid bacteria" see Family Acetobacteraceae (ex Henrici 1939) Gillis and De Ley 1980
             53 "Rickettsias" see Order Rickettsiales Gieszczykiewicz 1939 (Approved Lists 1980)
             54 "Methylomonads" see Order Methylococcales nom. inval.
             55 Genus Thermodesulforhabdus Beeder et al. 1996