In the Gram stain, is there any replacement for primary stain, secondary stain, decolourizer and mordant? What results will the replacements produce?

I found that crystal violet can be replaced with methylene blue but in that case, what will the secondary stain, mordant etc. be? Please also explain what result we might get.


As you may have realized, crystal violet can be replaced by a lot of dyes since the ethanol will wash out the dye from the gram negative cells. Methylene blue is a nice choice - malachite green may also work.

A weak concentration of hydrochloric acid (3%) is also a possible replacement for the ethanol. A 3% HCl solution is used in the acid-fast stain but it may be too strong for non-acid fast cells. It would be worth testing it out and trying it to see if it could replace the ethanol step.

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