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Yes. The gram stain procedure separates all bacteria into one of two groups - into gram-negative bacteria which do not stain purple and into gram-positive cells which do stain purple. In structural terms, the ability of a cell to become stained during the gram stain procedure is due to the chemical makeup of the cell wall.
What else can I help you with?
What is the purpose of control test in gram stain?
Gram staining is a simple staining test that simply identifies the two main groups of bacteria. Gram positive, and gram negative. Down a microscope, gram pos look like a dark blue/purple colour, and gram neg look red. It is to do with what the wall of the bacteria comprises of, and without going into too much detail, certain drugs work on gram pos bacteria, and others wont. Likewise for gram neg.
What color are bacterial endospores after a gram stain is performed?
Gram-staining does not stain the endospore due to the tough, resistant water-proof structure. It appears as an unstained area in a vegetative cell. Malachite green must be forced into the endospore with heat to stain it.
How does the Gram stain work What is happening as each reagent is used?
The positive turn purple and the negative turns red-colored. The positive is purple because the stain is able to pass through the thick peptoglycan wall where as the negative is red/pink because the stain can't get through the thick lipid layer (Membrane) to get to the thin peptoglycan layer.
Explain the mechanism of gram staining?
The slide is colored with purple and red stains, then examined under a microscope. The color of stain picked up and retained by the bacteria (purple or red), their shape (such as round or rectangle), and their size provide valuable clues to their identity
Is a Gram stain an adequate substitute for an acid fast stain?
So few organisms are acid-fast, the acid fast stain is used only when infection by an acid-fast organisms is suspected.
What does gram negative on a serratia marcescens gram stain mean?
Bacteria are gram positive or gram negative. Serratia happens to be a gram negative bacteria. They appear pink on a gram stain. Gram positive bacteria stain to a purple color on a gram stain. We can classify and ID bacteria using their gram stain and shape. Some antibiotics only work on gram negative bacteria and some only work on gram positive bacteria. It helps a doctor know which antibiotic to use.
Why would you want to know if a gram stain is positive or negative?
Gram negative bacteria (pink gram stain) contain no outer cell membrane, while gram positive bacteria (purple gram stain) do contain an outer cell membrane. Gram negative and positive bacteria can respond differently to antibiotics. Many only work on only one of the two bacteria types. A gram stain is also the first step in identifying a bacteria, dividing bacteria into two large and distinct groups.
What is the importance of iodine after primary stain?
Iodine is used after the primary stain in the Gram stain procedure to form a complex with the crystal violet dye, which helps to stabilize the dye within the bacterial cell wall. This step enhances the retention of the primary stain in Gram-positive bacteria.
What is the purpose of control test in gram stain?
Gram staining is a simple staining test that simply identifies the two main groups of bacteria. Gram positive, and gram negative. Down a microscope, gram pos look like a dark blue/purple colour, and gram neg look red. It is to do with what the wall of the bacteria comprises of, and without going into too much detail, certain drugs work on gram pos bacteria, and others wont. Likewise for gram neg.
What color are bacterial endospores after a gram stain is performed?
Gram-staining does not stain the endospore due to the tough, resistant water-proof structure. It appears as an unstained area in a vegetative cell. Malachite green must be forced into the endospore with heat to stain it.
How does the Gram stain work What is happening as each reagent is used?
The positive turn purple and the negative turns red-colored. The positive is purple because the stain is able to pass through the thick peptoglycan wall where as the negative is red/pink because the stain can't get through the thick lipid layer (Membrane) to get to the thin peptoglycan layer.
How does Gram stain work and how is it useful to doctors treating bacterial diseases?
A Gram is simply looking for the presence of peptidoglycans in the cell wall (Gram positive bacteria have them). This is useful for physicians attempting to characterize an infectious agent, and narrows down the possibility of species which may be diagnosed.
Explain the mechanism of gram staining?
The slide is colored with purple and red stains, then examined under a microscope. The color of stain picked up and retained by the bacteria (purple or red), their shape (such as round or rectangle), and their size provide valuable clues to their identity
Is a Gram stain an adequate substitute for an acid fast stain?
So few organisms are acid-fast, the acid fast stain is used only when infection by an acid-fast organisms is suspected.
Why does gram stain not work on mycobacterium tuberculosis?
Acid fast bacteria have a waxy coat on their cell wall, and their cell walls contain peptidoglycan. However, neither the crystal violet nor the counterstain (safranin) will penetrate the waxy layer. Therefore they will not be visible. An example of acid-fast bacteria are Mycobacteria. To visualize these bacteria, another staining technique called 'acid-fast staining' would be required.
Why do Gram positive bacteria retain crystal violet stain and remain purpule?
This is a fairly difficult question to answer. Most readings will only tell you that bile salts and crystal violet inhibit gram-positive growth but do not say why. I found some articles that probably would tell us why, but you must pay to subscribe to them. I do know why crystal violet inhibits gram-positive growth though. Crystal violet binds to the peptidoglycan layer of cell membrane in gram-positive bacteria (just like it does in the Gram stain). Gram-negative bacteria have an outer membrane that prevents the crystal violet from attaching to their peptidoglycan layer. Once crystal violet attaches to the peptidoglycan, enzymes called autolysins are unable to cut the polysaccharide linkages between the NAG and NAM residues. The cutting and reforming of the peptidoglycan layer is necessary for cell growth, thus killing the cell. I believe that bile salts work a very similar way just like how penicillin and lysozymes do.
Why do some antibiotics work better against gram positive then gram negative bacteria?
Part of describing the function of an antibiotic is stating whether it is effective against Gram-positive bacteria, Gram-negative bacteria or both. (There are other aspects such as whether there is effect on aerobic versus anaerobic bacteria (those that can versus cannot survive in the presence of oxygen), but I'll address that some other time).Some antibiotics have broad spectrum activity, being able to kill Gram-positive and Gram-negative bacteria. At first that might seem like a good thing, and indeed it is when you are treating an infection with an unknown bacterium. However, broad spectrum activity is not desirable when you know exactly what bacterium you are trying to eliminate. If possible, it's much better to target treatment more specifically against the offending bacterium for various reasons, such as to reduce the risk of resistance emerging in other bacterial groups.Some antibiotics are narrow spectrum. Some are most effective against Gram-positive or Gram-negative bacteria, with little activity against the other. In general, we want to use an antibiotic of the most narrow spectrum possible.
