The<unk>  are an order of Proteobacteria. Like all Proteobacteria, 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<unk>  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.
Legionellales
Fusobacteriota
Actinobacillus
Caulobacter
Lactobacillus
Lactucarium
Streptococcus
Clostridium