The family
Legionellaceae
is composed of a single genus,
Legionella
, and comprises 66 validly named species and three subspecies.
Legionella pneumophila
,
Legionella micdadei
,
Legionella bozemanii
, and
Legionella longbeachae
are the most important species from a clinical standpoint, with
L. pneumophila
causing more than 90% of Legionnaires' disease (LD) globally, apart from Australia and New Zealand, where
L. longbeachae
predominates. LD is a type of bacterial pneumonia caused by
L. pneumophila
and other
Legionella spp
. Identification of
Legionella spp
. in a clinical laboratory is optimally performed by observation of visual morphology, agglutination methods, and matrix‐assisted laser desorption ionization–time of flight mass spectrometry. Antimicrobial agents regarded as effective for treatment of LD are macrolides, fluoroquinolones, and, rarely, rifampin, all achieving adequate intracellular concentrations.