[Discovery of Legionella pneumophila: achievement in modern bacteriology].

The discovery of Legionella pneumophila is described and the clinical and epidemiological aspects of legionellosis (Legionnaire's disease) are presented. "New" pneumonia agents discovered after isolation and description of Legionella pneumophila, and which as yet lack definite designations, are mentioned. Up to June 1980, two additional bacilli not identical with Legionella pneumophila have been described and variously named, i.e. 1. WIGA (probably identical with ALLO), 2. TATLOCK (probably identical with HEBA and PPA). A third potential "new" pneumonia agent, named TEX-LK, must be added although it has been isolated in only one case of pneumonia.