[Nosocomial legionellosis]

Legionelosis is an environment-related disease with particular pulmonary tropism. Reporting is mandatory in France. Legionellosis may result from nosocomial or community-acquired infection. In both cases, humans are contaminated from a humid environmental reservoir that must be identified. Cellular immunity is the main mechanism of defense and transplant recipients, particularly those on an immunosuppressor regimen, are at risk. There is no clinical, biological or radiographic sign specific of nosocomial legionellosis. Culture provides the diagnosis. Treatment is based on prevention and curative antibiotic treatment using compounds with an intracellular activity. Preventive measures have been reinforced by legislation regulating the steps required in case of nosocomial legionellosis.