Table 1.

Current classification of Proteobacteria.

Phylum Proteobacteria
Class	α-Proteobacteria		Class	β-Proteobacteria
Orders	Caulobacterales	Rhizobiales	Orders	Burkholderiales	Neisseriales
	Kiloniellales	Rhodobacterales		Ferritrophicales	Nitrosomonadales
	Kopriimonadales	Rhodospirillales		Gallionellales	Procabacteriales
	Kordiimonadales	Rickettsiales		Hydrogenophilales	Rhodocyclales
	Magnetococcales	Sneathiellales		Methylophilales	Unclassified taxa
	Parvularculales	Sphingomonadales
	Unclassified taxa
Class	γ-Proteobacteria		Class	δ-Proteobacteria
Orders	Acidithiobacillales	Orbales	Orders	Bdellovibrionales	Desulfuromonadales
	Aeromonadales	Pasteurellales		Desulfarculales	Myxococcales
	Alteromonadales	Pseudomonadales		Desulfobacterales	Syntrophobacterales
	Cardiobacteriales	Salinisphaerales		Desulfovibrionales	Unclassified taxa
	Chromatiales	Thiotrichales		Desulfurellales
	Enterobacteriales	Vibrionales
	Legionellales	Xanthomonadales
	Methylococcales	Unclassified taxa
	Oceanospirillales
Class	ε-Proteobacteria		Class	ζ-Proteobacteria (candidatus)
Orders	Campylobacterales		Order	Mariprofundales
	Nautiliales
	Unclassified taxa