Comparison of the activity of three antibiotic regimens in severe Legionnaires' disease.

Comparison of the activity of different antibiotic regimens in Legionnaire's disease has never been made because of the rarity of well documented cases of that disease. We have retrospectively compared severe cases of Legionnaires' disease treated with pefloxacin alone or in combination with erythromycin and/or rifampicin using computer-matched cases treated either with erythromycin or with erythromycin in combination with rifampicin. This study suggests that: (1) combined therapy including erythromycin, rifampicin and/or pefloxacin is superior to therapy with erythromycin alone; (2) combinations including pefloxacin may be the most active ones; and (3) pefloxacin alone may be as active as combination therapy. Although these results are in agreement with data obtained in cell and in animal models of legionella infection they need to be further confirmed by the study of larger number of patients.