Spiramycin was compared with
erythromycin in a guinea pig model of severe Legionella pneumophila serogroup 1
infection. Male guinea pigs weighting 264-321 g were infected by the intraperitoneal route with 1.2 x 10(7) virulent L. pneumophila serogroup 1. Forty eight h after
infection, animals that had lost greater than or equal to 9% of their
body weight were randomly assigned to receive 48, 54 and 72 h after
infection intraperitoneal injections of (1) distilled water (n = 20), (2)
erythromycin lactobionate, 30 mg/kg per injection, (n = 22) or (3) the
injectable form of
spiramycin adipate, 30 mg/kg per injection (n = 22). Animals were observed daily for 15 days. All infected animals treated with distilled water died within four days of
infection. Of the 22 animals treated with
spiramycin, 10 (45.5%) died, and of the 22 animals treated with
erythromycin, 11 (50.0%) died of disseminated L. pneumophila
infection. In this animal model of very severe L. pneumophila
infection, the
injectable forms of
erythromycin and of
spiramycin gave similar results.
Spiramycin should therefore be considered for the treatment of
Legionnaires' disease in man.