[A case of legionnaire's disease in Germany (author's transl)].

Severe bronchopneumonia in a 66-year-old patient failed to respond to sensitivity-tested antibiotics, with only erythromycin providing improvement. The indirect immunofluorescence test for legionnaire's disease gave a highly significant titre rise (eightfold). Legionnaire's disease should be considered in the differential diagnosis of treatment-resistant bronchopneumonia.