Efeito da sulfadiazina e da pirimetamina, isoladamente e em associação, sobre isolados de Toxoplasma gondii obtidos de humanos com toxoplasmose congênita em Minas Gerais

Abstract

Toxoplasma gondii is the parasite responsible for toxoplasmosis, a disease with prevalence around the world and is of great interest on imunocompromised patients and pregnant women. Toxoplasmosis in Brazil presents great research interest because of the bigger severity of native cases, especially due to the predominant atypic genotypes. Toxoplasmosis is, usually, treated with the combination of Sulfadiazine and Pyrimethamin. However, for many reasons, a series of cases do not present satisfactory evolution and/or significant adverse effects, which can lead to treatment interruption. In this work, Swiss mice were infected with seven diferente strains of T. gondii, isolated from newborns with congenital toxoplasmosis (TgCTBr1, TgCTBr4, TgCTBr9, TgCTBr13, TgCTBr17, TgCTBr23, TgCTBr25), with atypic genotypes and virulent for mice. The animals were divide into 10 treatment groups: SDZ10, SDZ40, SDZ160, SDZ640 treated with 10 to 640mg/kg per day of Sulfadiazine; PM3, PM12, PM50, PM200 treated with 3 à 200mg/kg per day of Pirymethamin and SDZ+PM treated with a combination of the lower dosage of both drugs. The mice were evaluated for mortality and presence of brain cysts. ELISA and bioassays were also used to determine the efficacy of the therapeutic schemes. It was observed that the TgCTBr4 and TgCTBr17 strains (from the #108 genotype of ToxoDB - http://toxodb.org/toxo/) presented less susceptibility to treatment, while TgCTBr9 (with BrII genotype) was the one with most sensibility to treatment with both drugs. The association between Sulfadiazine e Pirymethamin, in reduced dosages, presented a more effective treatment for experimental toxoplasmosiswith T. gondii strains islated in Brazil.