Legionnaires' disease. A sporadic case.

A patient with Legionnaires' disease developed consolidated pneumonia with severe hypoxemia and mental confusion; his condition improved with therapy with positive end-expiratory pressure, steroids, and chloramphenicol. The retrospective diagnosis was made by a fourfold rise in indirect fluorescent antibody titers. The chest x-ray films showed bilateral alveolar infiltrates and air bronchograms.