Especially notable are Acetobacter, Agrobacterium, Aquospirillum, Brucella, Burkholderia, Caulobacter, Desulfovibrio, Gluconobacter, Hyphomicrobium, Leptothrix, Myxococcus, Neisseria, Paracoccus, Propionibacter, Rhizobium, Rickettsia, Sphingomonas, Thiobacillus, Xanthobacter and 268 additional genera.