Proteobacteria
A phylum of bacteria, composed of five classes.
Class Alphaproteobacteria, order Rhizobiales (families Bartonellaceae and Brucellaceae) and order Rickettsiales (families Anaplasmataceae and Rickettsiaceae).
Class Betaproteobacteria, order Burkholderiales (genera Alcaligenes, Bordetella, Taylorella and Burkholderia) and order Neisseriales.
Class Gammaproteobacteria, orders Pasteurellales, Pseudomonadales, Legionellales and Thiotrichales. It also includes the families Enterobacteriaceae and Vibrionaceae.
Class Deltaproteobacteria, order Myxobacteria (genus Myxococcus).
Class Epsilonproteobacteria, order Campylobacterales (families Campylobacteriaceae and Helicobacteriaceae).