Severe Legionnaires' Disease Successfully Treated with Levofloxacin and Azithromycin

Fluoroquinolones are the most active drugs against Legionella in intracellular and animal models, achieving high intracellular levels and low MICs. In patients with human immunodeficiency virus infection, Legionnaires' disease (LD) has a more severe clinical presentation and worse evolution, with a mortality rate of up to 20%. This chapter presents a case of a severely inmunosuppressed woman with LD in whom treatment failed with levofloxacin and who recovered after the addition of azithromycin. The intracellular location of the pathogen is relevant to the efficacy of the antibiotic. At present, new macrolides such as clarithromycin and azithromycin and fluoroquinolones are the most active drugs in the treatment of Legionella pneumonia. Even though the advances in rapid specific diagnosis and the greater efficacy of the new macrolides and quinolones have led to a better prognosis of Legionella pneumonia, mortality continues to be very high in immunosuppressed patients. Thus, randomized trials comparing the efficacy of combination therapies with new macrolides and quinolones versus monotherapy should be performed to evaluate their real impact in reducing morbidity and mortality of Legionella pneumonia with bad prognostic factors.