Order Chromatiales

Family Chromatiaceae
Allochromatium - Amoebobacter - Chromatium - Halochromatium - Isochromatium - Lamprobacter - Lamprocystis - Marichromatium - Nitrosococcus - Pfennigia - Rhabdochromatium - Rheinheimera - Thermochromatium - Thioalkalicoccus - Thiobaca - Thiocapsa - Thiococcus - Thiocystis - Thiodictyon - Thioflavicoccus - Thiohalocapsa - Thiolamprovum - Thiopedia - Thiorhodococcus - Thiorhodovibrio - Thiospirillum

Family Ectothiorhodospiraceae
Alkalilimnicola - Alkalispirillum - Aquisalimonas - Arhodomonas - Ectothiorhodosinus - Ectothiorhodospira - Halorhodospira - Natronocella - Nitrococcus - Thioalkalispira - Thioalkalivibrio - Thiohalospira - Thiorhodospira

Family Granulosicoccaceae
Granulosicoccus

Family Halothiobacillaceae
Halothiobacillus - Thiofaba - Thiovirga

Order "Enterobacteriales"

Family Enterobacteriaceae
Arsenophonus - Biostraticola - Brenneria - Buchnera - Budvicia - Buttiauxella - Calymmatobacterium - Cedecea - Citrobacter - Cronobacter - Dickeya - Edwardsiella - Enterobacter - Erwinia - Escherichia - Ewingella - Hafnia - Klebsiella - Kluyvera - Leclercia - Leminorella - Levinea - Moellerella - Morganella - Obesumbacterium - Pantoea - Pectobacterium - Photorhabdus - Plesiomonas - Pragia - Proteus - Providencia - Rahnella - Raoultella - Saccharobacter - Salmonella - Samsonia - Serratia - Shigella - Sodalis - Tatumella - Thorsellia - Trabulsiella - Wigglesworthia - Xenorhabdus - Yersinia - Yokenella

Order Legionellales

Family Coxiellaceae
Aquicella - Coxiella

Family Legionellaceae
Fluoribacter - Legionella - Sarcobium - Tatlockia

Unclassified Legionellales
Rickettsiella

Order Methylococcales

Family Crenotrichaceae
Crenothrix

Family Methylococcaceae
Methylobacter - Methylocaldum - Methylococcus - Methylohalobius - Methylomicrobium - Methylomonas - Methylosarcina - Methylosoma - Methylosphaera - Methylothermus