How does bacterium age affect gram staining results?

1. How does culture age affect the results of a gram stain?
2. Why is the age of the bacterial culture important in a gram stain?
3. Why must cultures between 18 24 hours old be used for the gram stain?
4. Why is time an important factor in Gram staining?
5. How are Gram (+) and Gram (-) microorganisms stained in Gram staining?
6. Which of these factors will affect your gram stain results?
7. Why should old cultures not be used for Gram staining?
8. Why Will old more than 48 hours cultures of Gram positive bacteria stain as gram-negative?
9. Why do gram-positive cells more than 24 hours old stain gram-negative?
10. Why do some bacteria retain the Gram stain while others do not?
11. Why is it important to know if a bacteria is Gram positive or negative?
12. Which step is most likely to cause poor results in the Gram stain?
13. How does safranin affect Gram-positive cells?
14. What is the factor behind an organism being Gram (+) or Gram?
15. What is the purpose of safranin in Gram staining?

How does culture age affect the results of a gram stain?

how does culture age affect the results of a gram stain? if the cultures are more than 16-18 hours old, then Gram-positive cultures can stain gram-variable or gram-negative and give false results. ... Thick smears can trap stain and falsely make cells appear gram positive.

Why is the age of the bacterial culture important in a gram stain?

In cultures of Bacillus, Butyrivibrio, and Clostridium a decrease in peptidoglycan thickness during growth coincides with an in increasing number cells that stain gram-negative (Beveridge, 1990). In addition, in all bacteria stained using the Gram stain, the age of the culture may influence the results of the stain.

Why must cultures between 18 24 hours old be used for the gram stain?

Why must young cultures be used in Gram staining? When gram positive bacteria become too old they stain Gram negative.

Why is time an important factor in Gram staining?

Do NOT decolorize for a full minute!

If the decolorizer is left on too long, even gram positive cells will lose the crystal violet and will stain red.

How are Gram (+) and Gram (-) microorganisms stained in Gram staining?

The Gram stain procedure distinguishes between Gram positive and Gram negative groups by coloring these cells red or violet. Gram positive bacteria stain violet due to the presence of a thick layer of peptidoglycan in their cell walls, which retains the crystal violet these cells are stained with.

Which of these factors will affect your gram stain results?

The many variables that can affect this stain are age of the culture, amount of decolorizer used, the time of decolorization, the type of organism (acid-fast bacteria and spores do not stain well), thickness of the smear, and the general care of the stainer.

Why should old cultures not be used for Gram staining?

Gram stain is reliable only on cells from cultures that are in the exponential phase of growth. Older cultures contain more ruptured and dead cells. Cells from old cultures may stain Gram negative even if the bacteria are Gram positive.

Why Will old more than 48 hours cultures of Gram positive bacteria stain as gram-negative?

Old cultures tend to lose the peptidoglycan cell walls, which predisposes gram-positive cells to be gram-negative or gram variable. Gram stain is not useful for organisms without a cell wall like Mycoplasma species, and for smaller bacteria like Chlamydia and Rickettsia species.

Why do gram-positive cells more than 24 hours old stain gram-negative?

Why will gram-positive cells more than 24 hours old stain gram-negative? The wall begins to degenerate after 24 hours. ... No because the iodine allows the crystal violet stain to bind to the peptidoglycan in cell walls. In gram-positive cells, the crystal violet turns the cells?

Why do some bacteria retain the Gram stain while others do not?

Why do some bacteria retain the Gram stain while others do not? The Gram stain absorbs into bacteria with a thick peptidoglycan layer, but does not absorb into bacteria with two cell membranes. ... Some bacteria prevent the growth of disease-causing bacteria, while some cause tooth decay by releasing acid.

Why is it important to know if a bacteria is Gram positive or negative?

The main benefit of a gram stain is that it helps your doctor learn if you have a bacterial infection, and it determines what type of bacteria are causing it. This can help your doctor determine an effective treatment plan.

Which step is most likely to cause poor results in the Gram stain?

Excessive Decolorization

It is clear that the decolorization step is the one most likely to cause problems in the Gram stain.

How does safranin affect Gram-positive cells?

How does safranin affect Gram-positive cells? Safranin penetrates the cell wall, but not enough of it is retained to cause a color change...... In the Gram-positive cell walls, most of the spaces between the molecules that make up peptidoglycan are already occupied by crystal violet/iodine complexes.

What is the factor behind an organism being Gram (+) or Gram?

In 1884, a bacteriologist named Christian Gram created a test that could determine if a bacterium had a thick, mesh-like membrane called peptidoglycan. Bacteria with thick peptidoglycan are called gram positive. If the peptidoglycan layer is thin, it's classified as gram negative.

What is the purpose of safranin in Gram staining?

It helps the microbiologists stain the decolorized gram-negative bacteria during Gram's staining.