[Legionella infections].

The authors review the bacteriological features of Legionella infections, their clinical symptoms and the methods of diagnosis. They stress the unusual ecological features of Legionella which generally lives in natural water reservoirs or in artificial reservoirs (drinking water piping, air conditioning). In the clinical situation, current emphasis is on the extrapulmonary infections whose pathogenesis has not yet been fully explained. The incidence and prevalence of Legionella in pneumonia still needs to be defined. The methods of bacteriological and serological diagnosis are described as well as the ways of interpreting the results.