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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.
Wiki User
∙ 16y ago
Wiki User
∙ 11y agoMycobacteria do not "take" the stain - i.e - it will not color them. To see mycobacteria you need to use acid fast stain.
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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.
Does the gram stain procedure work for all bacteria?
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 is the cause for TB?
The Mycobacterium tuberculosis bacterium causes TB. It is spread through the air when a person with TB (whose lungs are affected) coughs, sneezes, spits, laughs, or talks.TB is contagious, but it is not easy to catch. The chances of catching TB from someone you live or work with are much higher than from a stranger. Most people with active TB who have received appropriate treatment for at least 2 weeks are no longer contagious.
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 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 is an acid-fast pathogen?
An acid-fast pathogen is a bacteria that is harmful to humans. They have cell walls that contain mycolic acid which is a lipid. Common Gram type staining techniques wont work with these cells. A special stain carbolfuchsin is used to penetrate the wall.After staining you wash with acid alcohol if the stain remains it is acid fast if it washes out it is non-acid fast.Mycobacterium tuberculosis is a well known acid-fast pathogen
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 do surfactants work in stain removers?
Surfectants work in stain removers to remove the stain and not damage what the stain is on. It oxidizes the stain and lifts it out of whatever its in,
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.
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.
How does stain remover work?
A stain remover may be a solvent which dissolve the stain or a substance which react with the stain.
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.
