Certain protozoa, specifically Cryptosporidium, Toxoplasma, and Eimeria, are acid-fast due to the unique composition of their oocyst walls.
Acid-Fastness in Protozoa: The Case of Oocyst Walls
The acid-fast characteristic in these protozoa is attributed to the structure of their oocyst walls. These walls contain a rigid bilayer that shares similarities with the outer membrane of mycobacteria, the bacteria known for their acid-fastness. This structural similarity is responsible for their ability to resist decolorization by acid-alcohol after staining with dyes like Ziehl-Neelsen stain.
Key Protozoa with Acid-Fast Oocysts
- Cryptosporidium: Well-known for its acid-fast oocysts.
- Toxoplasma: Oocysts also exhibit acid-fast properties.
- Eimeria: Similar to Cryptosporidium and Toxoplasma, Eimeria oocysts are acid-fast.
It's important to note that the oocyst walls of Cryptosporidium and Eimeria are susceptible to disruption by organic solvents.
