Legionellales

Legionellales
Legionella sp. under ultraviolet illumination
Scientific classification
Domain: Bacteria
Kingdom: Pseudomonadati
Phylum: Pseudomonadota
Class: Gammaproteobacteria
Order: Legionellales
Families and genera

Legionellaceae
   Legionella
Coxiellaceae
   Aquicella
   Coxiella
   Diplorickettsia
   Rickettsiella
   "Ca. Berkiella"
   "Ca. Fiscibacter"
   "Ca. Ovatusbacter"
   "Ca. Pokemonas"

The Legionellales are an order of Pseudomonadota ("Proteobacteria"). Like all Pseudomonadota, they are Gram-negative. They comprise two families, typified by Legionella and Coxiella, both of which include notable pathogens. For example, Q fever is caused by Coxiella burnetii and Legionella pneumophila causes Legionnaires' disease and Pontiac fever.

Members of the order Legionellales can be molecularly distinguished from other Gammaproteobacteria by the presence of four conserved signature indels (CSIs) in the proteins tRNA-guanine(34) transglycosylase, lipoprotein-releasing system transmembrane protein lolE and tRNA (guanosine(37)-N1)-methyltransferase TrmD.