Why must fresh bacterial cultures be used in a Gram stain?

Answer 1

Why must young cultures be used when doing a Gram stain Young cultures must be used so the crystal violet can stick to the cell walls of Gram positive bacteria. The cell walls break down in old cultures and the staining process is not accurate

Answer 2

Cultures that are older have the possibility to turn from Gram Postive to Gram Negative thus altering the results of the Gram staining test.

----Rock on University of Pangasinan BMLS students

Answer 3

Gram variables could make bacteria change from one result to another.

Say for example a culture yields a gram negative result while it is still young.

But after a period of time you could be seeing gram positive (it got "old").

To get an accurate result, one should gram stain bacteria while it is still young to avoid missing out on the first result and could note any gram variable properties in case a different result was obtained later.

I couldn't find any actual articles that support this yet, but my tutor told me this. !

Answer 4

Young cultures must be used when doing a gram stain to get more accurate results. The cell was is the part of the bacterial cell that is most involved with gram staining because it holds the crystal violet.

Answer 5

As the bacteria age, their peptidoglycan wall breaks down so that it doesn't quite hold the violet crystals. For instance, Strep pneumoniae will stain Gram negative even though it is a Gram positive organism because it peptidoglycan wall starts to break down over time.

Answer 6

Cultures that are older have the possibility to turn from Gram Postive to Gram Negative thus altering the results of the Gram staining test.