Determination of the activity of pyrimethamine, trimethoprim, sulfonamides, and combinations of pyrimethamine and sulfonamides against Sarcocystis neurona in cell cultures.

This research article discusses the impact of various medicines, including pyrimethamine, trimethoprim, sulfonamides, and their combinations on the apicomplexan parasite, Sarcocystis neurona, which often causes Equine protozoal myeloencephalitis (EPM) in horses from the Americas. The experiment was conducted using the bovine turbinate cell cultures and presented methods to evaluate the drug activities against S. neurona.

Objective of the Research

• The aim of this research was to assess the efficacy of different drugs – pyrimethamine, trimethoprim, sulfonamides, and their combinations – against the parasite Sarcocystis neurona that causes EPM syndrome in horses.

Methodology and Approach

• Multiple drugs were screened for their effect against developing S. neurona merozoites in bovine turbinate cell cultures.
• Two types of assays were conducted – a microtiter plate host cell lesion based assay and a cell culture flask assay to reveal the impacts of these agents on the merozoites.
• The microtiter plate assay focused on determining the effect of the drugs on the developing merozoites.
• The cell culture flask assay concentrated on identifying if selective concentrations of the agents killed or merely stopped the development of the S. neurona.

Key Findings

• Result analysis demonstrated that pyrimethamine at 1.0 microg/ml concentration and trimethoprim at 5.0 microg/ml concentration were effective against the parasite.
• Sulfonamides did not display any significant effect when used alone at high concentrations of (50.0 or 100.0 microg/ml).
• However, the experiment indicated that a combination of sulfonamides with a minimal concentration of pyrimethamine (0.1 microg/ml) shown improved activity against S. neurona.