Growth of Trypanosoma cruzi in vitro: development and application of a continuous-flow culture system

The design and operation of a modular, bacteriological continuous-flow culture system have been adapted for the growth of Trypanosoma cruzi epimastigotes in simple monophasic media. The system was designed to achieve a minimum of 200 days of continuous culture and provision was made for the continuous supply of medium and collection of parasites under sterile conditions. The system provides large quantities of epimastigotes with homogeneous morphology and uniform viability. The system also lends itself to the analysis of the factors which affect parasite growth. We examined the effects of changes in environmental parameters on epimastigote growth rate. Optimal growth was observed at 27 degrees C. The rate of stirring of the culture had a small but definable effect on the growth rate, which was greatest at 80 rp.m. Growth was only slightly affected by the level of dissolved oxygen between 10 and 50% saturation, but was inhibited at higher concentrations. Growth was slower at extreme values of pH but showed a broad optimum around pH 7.4.