[Treatment of experimental brucellosis of mice and guinea pigs by rifampicin].

The intracellular and bactericidal activity of rifampicine was observed in the treatment of experimental brucellosis in the mouse and guinea pig. Batches of mice infected by intraperitoneal route with B. melitensis, strain 53 H 38, were treated with rifampicine (20 mg/kg/day) or with tetracycline-base (200 mg/kg/day). When the treatment begins 14 days after inoculation and lasts a week, the rifampicine produces a more significant decrease of the weight of the spleen than does tetracycline. After 14 days' treatment, apart from this effect, the degree of infection of the spleen decreases at least 10(5) times with rifampicine and 10(2) times with tetracycline. After 21 days, bacteriological sterilization is obtained with rifampicine whereas 66% of the tetracycline-treated mice are still infected. However, a residual infection of weak intensity persists in 6.6% of the rifampicine-treated mice against 75% of the tetracycline-treated mice, as shown by an injection of Corynebacterium parvum and a cortisone treatment at the end of the antibiotherapy. If the antibiotic treatment begins on the day of inoculation, the greatly superior efficacity of rifampicine is in that case more rapid. Rifampicine (100 mg/kg/day) offers comparable efficacity in the guinea pig infected by intraperitoneal route with B. abortus strain 544; these efficacity is shown by the decrease in the weight of the spleen and the intensity of splenic and ganglionic infection. The rapid decrease of agglutinins and amboceptors after 7 days of treatment suggests the possible role of a suppressor of this antibiotic. Finally, the effect of rifampicine on the growth of the guinea pig was noted.