[Legionella pneumonia successfully treated despite late diagnosis]

Status asthmaticus developed in a 72-year-old man who was being treated with oral prednisolone for severe persistent asthma. The dosage of prednisolone was increased, and amikacin was injected to treat pneumonia that had developed in the right lung. Progressive pulmonary infiltrates, respiratory compromise, and hypoxemia developed, and the patient eventually required mechanical ventilation. Antibiotic treatment was changed to imipenem/cilastatin, piperacillin, gentamicin, clarithromycin, erythromycin, and minocycline. Liver injury developed. More than one month after the patient was admitted, Legionella pneumonia was diagnosed. Levofloxacin (400 mg/day) was then given orally, in combination with injected imipenem/cilastatin. Liver function did not deteriorate, and the pneumonia resolved. Most diagnoses of Legionnaires' disease are made retrospectively by examination of serum. In this case, antibiotics active against Legionella pneumophila had been used before the diagnosis was established, which probably contributed to the patient's recovery. When aminoglycosides or beta-lactam antibiotics are ineffective, administration of agents effective against Legionnaires' disease should be considered.