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PEHPS medium: an alternative for axenic cultivation of Entamoeba histolytica and E. invadens
S Said-Fernández1, J Vargas-Villarreal, J Castro-Garza
1División de Biologia Celular, Instituto Mexicano del Seguro Social, Monterrey, Nuevo León, México.
Abstract:
Knowledge of Entamoeba histolytica biology in the last 17 years has been acquired largely as a consequence of this parasite's axenic cultivation in TPS-1 or TYI-S-33 media. Unfortunately, there are often low yields in these media, due to variability of their main components, Panmede and yeast extract. We describe a medium, PEHPS, of which the main components are extracts of ox liver, and ox and swine pancreas (EHP). 5 strains of E. histolytica and 2 of E. invadens were quickly and easily adapted to PEHPS and serially cultivated for 3 years. Yields progressively rose initially, and then became stable. Depending on the strain, average yields in the last 6 months of this study were 1.3 to 3.1 x 10(5) amoebae/ml for E. histolytica and 5.5 to 5.7 x 10(5) for E. invadens. All the 18 EHP batches tested supported vigorous amoebal growth. PEHPS had 2 additional advantages: (a) it was stable at 4 degrees C or 25 degrees C for 9 months, and at -10 degrees C for at least 2 years, and (b) it supported amoebal growth with inocula as low as one trophozoite/ml. PEHPS avoids the variability shown by TPS-1 and TYI-S-33, and could therefore be a good alternative for axenic amoebal cultivation.
Insights
A new culture medium, PEHPS, using liver and pancreas extracts (EHP), supports Entamoeba histolytica growth. This axenic cultivation method offers stable, high yields and improved storage compared to existing media.
Area of Science:
- Microbiology
- Parasitology
- Cell Culture
Background:
- Entamoeba histolytica axenic cultivation relies on TPS-1 or TYI-S-33 media.
- These media exhibit component variability, leading to inconsistent and often low parasite yields.
- Improved culture methods are crucial for advancing Entamoeba histolytica research.
Purpose of the Study:
- To develop and evaluate a novel axenic culture medium for Entamoeba histolytica and Entamoeba invadens.
- To address the limitations of existing culture media regarding yield and stability.
- To provide a reliable alternative for parasite cultivation.
Main Methods:
- A new medium, PEHPS, was formulated using extracts of ox liver and ox/swine pancreas (EHP).
- Five strains of E. histolytica and two of E. invadens were adapted to PEHPS.
- Parasites were serially cultivated for three years, with yields and growth characteristics monitored.
Main Results:
- PEHPS supported rapid adaptation and serial cultivation of all tested Entamoeba strains.
- Parasite yields increased initially and then stabilized, reaching 1.3-3.1 x 10^5 amoebae/ml for E. histolytica and 5.5-5.7 x 10^5 for E. invadens.
- PEHPS demonstrated excellent stability at various temperatures and supported growth from low inocula.
Conclusions:
- PEHPS is a robust and reproducible medium for axenic cultivation of Entamoeba species.
- It overcomes the variability issues associated with TPS-1 and TYI-S-33 media.
- PEHPS offers a promising alternative for Entamoeba histolytica research and diagnostics.