Molecular characterization of susceptible and naturally resistant strains of Trypanosoma cruzi to benznidazole and nifurtimox

Trypanosoma cruzi benznidazole susceptibility in vitro does not predict the therapeutic outcome of human Chagas disease

“…These values are of the same order of magnitude of IC 50 of epimastigotes in stocks belonging to different DTU (Villarreal et al 2004). Some studies reported that DTU I isolates were more resistant to BZ than parasites of the other DTUs (Toledo et al 2003(Toledo et al , 2004, whereas others showed no correlation between in vitro drug susceptibility and T. cruzi groups (Murta et al 1998, Villarreal et al 2004. Our data support the latter conclusion.…”

“…One primary explanation may be the presence of different parasite lineages in different geographic regions, with T. cruzi I predominating in Central America and T. cruzi II in South America (Carranza et al 2009 and cited references). In fact, variations in drug susceptibility among T. cruzi strains have been documented widely in in vitro and in vivo studies (Filardi & Brener 1987, Murta et al 1998, Toledo et al 2003, Villarreal et al 2004. Another factor to consider is the time between vector control activity and drug treatment because cases (mostly asymptomatic) treated closer to the time of the acute phase of the disease might account for more rapid cure.…”

Ergosterol biosynthesis and drug development for Chagas disease

“…However, their efficacies vary according to geographical area, most likely due to differences in drug susceptibility among different T. cruzi strains (Filardi & Brener 1987, Murta et al 1998, Kirchhoff 1999. Moreover, it has been reported in the last 15 years that BZN also exhibits significant curative activity in those with recent onset (up to a few years) of chronic disease; 60-70% of radical parasitological cures have been observed among children up to 14 years of age in Brazil and Argentina (de Andrade et al 1996, Andrade & Zicker 1997, Sosa Estani et al 1998, Sosa Estani & Segura 1999, Andrade et al 2004).…”

Estudio de la variabilidad de seis cepas colombianas de Trypanosoma cruzi mediante polimorfismos de longitud de fragmentos de restricción (RFLP) y amplificación aleatoria de ADN polimórfico (RAPD).

“…Estos resultados sugieren que el comportamiento del parásito en Colombia difiere del de los otros países de Suramérica, especialmente de los países del Cono Sur, en donde diferentes estudios muestran correlación entre los resultados de isoenzimas y los de RAPD (13,14,(29)(30)(31). Adicionalmente, vale la pena resaltar cómo si bien todas las cepas analizadas pertenecen al zimodema ZI, no se presentaron perfiles de RAPD iguales entre ellas, lo cual indica que su heterogeneidad es muy alta, a diferencia de los estudios de Brisse et al (32) y Bosseno et al (33), quienes informaron un alto grado de homogeneidad entre los RAPD de cepas pertenecientes al zimodema I.…”