Gram-staining bacteria?

Question

1.Which is the most critical step in the Gram-stain procedure? Why? If this procedure is done incorrectly, how might that affect the final results?

2.How does culture age affect the results of a Gram-stain?

Answer 1

The most critical step is probably the decolorization step.  If done for too long, everything will appear as gram negative.  If done for too short a time, the results may appear all gram positive.

As cultures age, the gram reactions become less consistent, and you may see what appears to be a mixture of organisms when in fact it is a pure culture.