Schizodeme analysis of Trypanosoma cruzi Colombian strain clones isolated from the acute phase of murine infection

Colombian strain of Trypanosoma cruzi, biodeme Type III (T. cruzi I), has been cloned by micromanipulation at two phases of the acute infection: early (10 days ) and advanced (30 days). Twelve clones were obtained therefrom. Characterization by their biological and biochemical behavior showed an identity among the several clones and their parental strain, albeit with different degrees of virulence. Molecular characterization of the kinetoplast DNA (kDNA) after amplification by polymerase chain reaction revealed identical profiles of the bands from the kDNA minicircle by the analysis of restriction fragment lenght polymorphism for the isolated clones, their parental strain, and to the clones isolated at two different phases of the infection. Results suggest the predominance of a "principal clone", in the composition of the Colombian strain, responsible for the biological and biochemical behavior. However, no relationship was detected between the molecular profile of kDNA and the degree of virulence presented by the several clones.

Trypanosoma cruzi: susceptibility to chemotherapy with benznidazole of clones isolated from the highly resistant Colombian strain

The present investigation was performed to evaluate the susceptibility of seven clones isolated from the highly resistant Colombian strains, prototype of Biodeme Type III. Seven clones previously obtained, showed a phenotypic homogeneity and high similarity with the parental strain. Eight groups of 30 mice were inoculated with one of seven clones or the parental strain; 20 were treated with benznidazole (100mg/kg/day) and 10 were untreated controls. Cure evaluations were done by parasitological and serological tests and PCR. Cure rates varied from 0 percent (null) to 16.7 percent. Correlation between positivity of parasitological and serological tests with positive PCR reached 37 percent. The results demonstrated the high resistance of the clones, suggesting the predominance of a highly resistant principal clone in this strain. The findings apparently indicate that the possibility of cure is minimal for patients infected with this biodeme; a fact that could affect the control of Chagas' disease through treatment of chronically infected people