Background
Legionella is a ubiquitous Gram-negative bacterium naturally found in aquatic environments.
It can pose a health problem when it grows and spreads in man-made water systems. Legionella pneumo-phila is the most common cause of Legionnaires’ disease nowadays, a community-acquired pneumonia with pulmonary symptoms and chest radiography no different from any other form of infectious pneumonia.
Legionella monitoring is important for public health reasons, including the identification of unusual envi-ronmental sources of Legionella.