Azithromycin prophylaxis and treatment of murine toxoplasmosis

OBJECTIVE: To evaluate the azithromycin effects alone and in combination with other agents in the prophylaxis and treatment of murine toxoplasmosis.

METHODS: A total of 280 BALB/c mice were included, and 2 x 103 Toxoplasma organisms of the RH strain Toxoplasma gondii strain ATCC50174 were given intraperitoneally to each mouse. In experiment one, 40 animals were given azithromycin 200 milligram/kilogram/daily for 3 days starting the day of inoculation, 40 mice were control. In experiment 2, the treatment was started 48 hours after inoculation and given daily for 3 days: one group received azithromycin 200 milligram/kilogram/day, the second group received pyrimethamine 25 milligram/kilogram/day, and the sulfadiazine 100 milligram/kilogram/day. The third group was control. In experiment 3, 7 groups of animals received one of the following (1) none, (2) azithromycin 200 milligram/kilogram/day, (3) pyrimethamine 25 milligram/kilogram/day and sulfadiazine 100 milligram/kilogram/day, (4) azithromycin and sulfadiazine, (5) azithromycin and pyrimethamine, (6) azithromycin with sulfadiazine and pyrimethamine, (7) sulfadiazine alone. Treatment was initiated 72 hours after inoculation for 3 days. The study was conducted at the Animal Care Facility of King Saud University, Riyadh, Kingdom of Saudi Arabia.

RESULTS: Animals that received azithromycin simultaneously with inoculation survived, and all control animals died. All animals died in groups receiving single drug therapy. Animals treated with azithromycin and sulfadiazine showed a survival rate of 40%, sulfadiazine and pyrimethamine 40%, or azithromycin with sulfadiazine and pyrimethamine 95% (p<0.0001).

CONCLUSION: Azithromycin alone was found to be effective in the prophylaxis of murine toxoplasmosis. Combination therapy was effective in the treatment of murine toxoplasmosis.