Proteobacteria

A phylum of bacteria, composed of five classes.

Class Alphaproteobacteria, orders Rhizobiales and Rickettsiales.

Class Betaproteobacteria, orders Burkholderiales and Neisseriales.

Class Gammaproteobacteria, orders Pasteurellales, Pseudomonadales, Legionellales and Thiotrichales. It also includes the families Enterobacteriaceae and Vibrionaceae.

Class Deltaproteobacteria, order Myxobacteria.

Class Epsilonproteobacteria, order Campylobacterales (families Campylobacteriaceae and Helicobacteriaceae).