Combination of PS-15, epiroprim, or pyrimethamine with dapsone in prophylaxis of Toxoplasma gondii and Pneumocystis carinii dual infection in a rat model.
In a rat model of dual infection, we studied such dihydrofolate reductase (DHFR) inhibitors as PS-15 (25 mg/kg of body weight), epiroprim (100 mg/kg), and pyrimethamine (3 mg/kg) alone or in combination with various doses of dapsone (50, 25, or 5 mg/kg) for the prevention of pneumocystosis and toxoplasmosis. Rats latently infected with Pneumocystis carinii were immunosuppressed by corticosteroids for 7 weeks, and the drugs were administered from the initiation of the corticosteroid treatment. At week 5, the rats were inoculated intraperitoneally with the RH strain of Toxoplasma gondii. Infections were monitored by the counting of P. carinii cysts in lung homogenates and the titration of T. gondii in organs by quantitative culture and an indirect immunofluorescence assay. Fourteen of the 15 untreated rats died after T. gondii challenge, with P. carinii infection in the lungs and T. gondii infection in the lungs, liver, spleen, and brain. Of the three tested DHFR inhibitors, only PS-15 exhibited anti-P. carinii activity; none prevented toxoplasmosis in 100% of the rats. After the DHFR inhibitors were combined with dapsone (50 or 25 mg/kg), both pneumocystosis and toxoplasmosis were completely prevented. On the basis of these results, PS-15 and epiroprim combined with dapsone are candidates for use for the prevention of both pneumocystosis and toxoplasmosis.
Brun-Pascaud
M
M
Institut National de la Santé et de la Recherche Médicale Unité 13, Hôpital Bichat, Paris, France.
Chau
F
F
Garry
L
L
Jacobus
D
D
Derouin
F
F
Girard
P M
PM
D000818:Animals; D000900:Anti-Bacterial Agents; D000981:Antiprotozoal Agents / Q000008:administration & dosage / Q000627:therapeutic use; D003622:Dapsone / Q000008:administration & dosage / Q000627:therapeutic use; D004359:Drug Therapy, Combination / Q000627:therapeutic use*; D005493:Folic Acid Antagonists / Q000008:administration & dosage / Q000627:therapeutic use*; D007165:Immunosuppression Therapy; D016720:Pneumocystis Infections / Q000150:complications / Q000382:microbiology / Q000517:prevention & control*; D002727:Proguanil / Q000008:administration & dosage / Q000031:analogs & derivatives / Q000627:therapeutic use; D011739:Pyrimethamine / Q000008:administration & dosage / Q000627:therapeutic use; D051381:Rats; D017208:Rats, Wistar; D013762:Tetrahydrofolate Dehydrogenase / Q000378:metabolism; D014122:Toxoplasma; D014124:Toxoplasmosis, Animal / Q000150:complications / Q000469:parasitology / Q000517:prevention & control*; D014295:Trimethoprim / Q000008:administration & dosage / Q000031:analogs & derivatives / Q000627:therapeutic use
D000900:Anti-Bacterial Agents; D000981:Antiprotozoal Agents; D005493:Folic Acid Antagonists; C082651:PS 15; D003622:Dapsone; C082896:epiroprim; D014295:Trimethoprim; D013762:Tetrahydrofolate Dehydrogenase; D002727:Proguanil; D011739:Pyrimethamine