Treatment of legionnaires' disease.

Erythromycin has been the most commonly used drug for the treatment of legionnaires' disease; however, failures have occurred and adverse effects are common. Doxycycline intravenously is preferred and is less expensive. The newer macrolides/azalides, clarithromycin and azithromycin, have excellent in vitro activity against Legionella and fewer adverse effects than erythromycin. The fluoroquinolones, particularly levofloxacin, are the most active anti-Legionella antibiotics available. Other agents with activity against Legionella pneumophila include minocycline, rifampin, and trimethoprim-sulfamethoxazole. The preferred therapy of legionellosis in immunocompromised patients are quinolone/macrolide combinations, eg, levofloxacin plus azithromycin.