[Diseases of the lungs caused by legionella species (author's transl)].

Ever since the 1976 Philadelphia epidemic and the isolation of the causative organism by MacDade in 1977, numerous clinical, epidemiological and bacteriological papers have stressed the significance of the "new" causative organisms responsible for serious cases of pneumonia. On the basis of knowledge available at present, the Legionellaceae family accounts for these bacteria. There are five different species in the genus Legionella: L. pneumophila, L. micdadei, L. bozemannii, L. dumoffii and L. gormanii. L. pneumophila occurs most frequently and has six serogroups (Serogroups 1-6), the first of which is the most important. Legionelloses, the diseases caused by these organisms, occur epidemically, endemically or sporadically. In clinical terms, these are acute cases of pneumonia which occur especially frequently in older persons and immunocompromised hosts. The course is severe in such patients. There is increased lethality. Erythromycin, rifampicin and cefoxitin are the most effective antibiotics. After the culture has been made in the suitable milieu and the material obtained by pulmonary aspiration has been inoculated into guinea pigs, the bacteriological diagnosis is made by direct immunofluorescence. The serological diagnosis is based on evidence of serological changes demonstrated by the indirect immunofluorescence test.