Endospore staining

Endospore staining is a technique used in bacteriology to identify the presence of endospores in a bacterial sample, which can be useful for classifying bacteria.^[1] Within bacteria, endospores are quite protective structures used to survive extreme conditions, but this protective nature makes them difficult to stain using normal techniques. Special techniques for endospore staining include the Schaeffer–Fulton stain and the Moeller stain. A good stain to use for spore staining is malachite green. It takes a long time for the spores to stain due to their density, so time acts as the mordant when doing this differential stain; the slide with the bacterium should be soaked in malachite green for at least 30 minutes. Water acts as the decolorizer. A counterstain to differentiate the vegetative cells is 0.5% safranin. Types of endospores that could be identified are free endospores, central endospores, central and swollen endospores, and subterminal endospores. One obstacle of this stain is if staining Mycobacterium because due to the its thick, wax coats, some cells will stain green, looking positive for spores although this particular bacterium does not produce .

References

1. Hussey, Marise; Zayaitz, Anne (2011-09-29). "Endospore Stain Protocol". American Society for Microbiology. Retrieved 2012-03-06.