The smear is then rinsed with a very strong decolorizer, which strips the stain from all non-acid-fast cells but does not permeate the cell wall of acid-fast organisms. ... The decolorized non-acid-fast cells then take up the counterstain, which in our case is methylene blue.

Which Decolorizer is used in AFB staining?

Step 1. Apply carbol fuchsin to a fixed slide for 1 minute followed by rinsing. Step 2. The decolorizing agent, 3% hydrogen chloride (HCl), is applied for 2 minutes and remove the primary stain and rinse.

What is acid alcohol Decolorizer?

Description. Acid alcohol decolorizer is used to differentiate dyes in various staining methods such as the AFB and regressive H&E staining methods.

What is the primary stain the Decolorizer and the counterstain in the acid-fast procedure?

The unique ability of mycobacteria to resist decolorization by acid-alcohol is why they are termed acid-fast. It involves the application of a primary stain (basic fuchsin), a decolorizer (acid-alcohol), and a counterstain (methylene blue).

How do you make an acid-fast Decolorizer?

The (3% Acid- Alcohol Decolorizer) is commonly used for the Mycobacterium tuberculosis. The 0.5% Acid- Alcohol Decolorizer is commonly used for the Mycobacterium leprae is simply prepared by adding 0.5 ml of concentrated Hydrochloric acid (HCl) in 99.5 ml of Absolute Ethanol in an Erlenmeyer flask.

Acid-Fast Stain

What is composed of Mycolic acids?

Mycolic acids are long fatty acids found in the cell walls of the Mycolata taxon, a group of bacteria that includes Mycobacterium tuberculosis, the causative agent of the disease tuberculosis. ... Mycolic acids are composed of a longer beta-hydroxy chain with a shorter alpha-alkyl side chain.

What does the Decolorizer do in Gram staining?

A decolorizer such as ethyl alcohol or acetone is added to the sample, which dehydrates the peptidoglycan layer, shrinking and tightening it. The large crystal violet-iodine complex is not able to penetrate this tightened peptidoglycan layer, and is thus trapped in the cell in Gram positive bacteria.

What is a flagella stain?

The flagella stain allows observation of bacterial flagella under the light microscope. Bacterial flagella are normally too thin to be seen under such conditions. The flagella stains employs a mordant to coat the flagella with stain until they are thick enough to be seen. ... Flagella can vary by number and location.

What is Endospore staining in microbiology?

Endospores staining is the type of staining to recognize the presence spore in bacterial vegetative cells. The bacterial endospores need a staining which can penetrate wall thickness of spore bacteria. A method of endospores staining is Schaeffer Fulton method that used Malachite Green.

Is acid alcohol a Decolorizer?

All lot numbers of TB Decolorizer (3% Acid Alcohol) have been tested and have been found to yield acceptable stain results as listed in the Interpretation section. Quality control testing should be performed following procedures established by each laboratory according to applicable regulatory guidelines.

What is Ziehlneelsen staining?

Ziehl–Neelsen staining is a bacteriological stain used to identify acid-fast organisms, mainly Mycobacteria. It is named for two German doctors who modified the stain: the bacteriologist Franz Ziehl (1859–1926) and the pathologist Friedrich Neelsen (1854–1898).

How do you make acid ethanol?

Acid alcohol: Mix 2.0 mL concentrated hydrochloric acid and 98.0 mL 95% ethyl alcohol. 3. Methylene blue: Prepare a saturated solution of methylene blue by adding 1.5 g powdered methy- lene blue to 100 mL 95% ethyl alcohol. Slowly add the alcohol to dissolve the powder.

What is the Decolorizer used in Endospore stain?

It takes a long time for the spores to stain due to their density, so time acts as the mordant when performing this differential stain; the slide with the bacterium should be soaked in malachite green for at least 30 minutes and then rinsed off with water which acts as the decolorizer.

Why do we use acid alcohol in acid fast staining?

Acid alcohol has the ability to completely decolorize all non-acid-fast organisms, thus only leaving behind red-colored acid-fast organisms, like M. tuberculosis. The slides are then stained a second time with methylene blue that serves as a counterstain.

Why is acid alcohol used instead of 95 ethyl alcohol for Decolorizing the primary stain?

Why is acid-alcohol rather than ethyl alcohol used as a decolorizing agent? The primary stain is more soluble in cellular waxes than acid-alcohol, so the stain is able to penetrate mycobacteria and not be washed away with the use of acid-alcohol. ... Microscopic examination of the child's sputum reveals no acid-fast rods.

What do you stain flagella with?

Since flagella are too thin to be seen by compound light microscopy, staining methods employ the use of a mordant (often tannic acid) to make them thick enough to see using an oil immersion objective.

What is the Counterstain primary stain and Decolorizer in that order in the Endospore stain?

Endospores are stained using malachite green, heat is used to penetrate the stain. What happens to the cell? The cells is decolorized and counterstained a light red with safranin.

What are the three parts of a flagellum?

Flagella are the organelles for bacterial locomotion. These supramolecular structures extend from the cytoplasm to the cell exterior and are composed of three major structural elements, the basal body, the hook and the filament (Fig. 1).

Which of the following is used as counter stain in Gram staining?

For instance, in Gram staining, two dyes are used: the Crystal Violet and Safranin. The Safranin is the counterstain used in this method.

What is the role of phenol in acid-fast staining?

In acid fast stains, the phenol allows the stain to pen- etrate, even after exposure to decolourisors. If an organism is to be termed Acid Fast, it must resist decolourisation by acid-alcohol. A counterstain is then used to emphasise the stained organism.

What is the Decolorizer in the Gram stain quizlet?

The decolorizer is Ethanol. It is added to chemically change the shape of the dye molecule and trap it in the cell wall. Iodine is used in the Gram stain.

What is ethanol in Gram staining?

Ethyl alcohol is a nonpolar solvent, and thus penetrates the cell walls of Gram negative cells more readily and removes the crystal violet-iodine complex. However, caution must be used since applying the decolorizer too long will remove dye complexes from the Gram positive cells as well.

How do you make a Gram stain Decolorizer?

Gram Decolorizer Solution: Mix equal volumes of 95 % ethanol and acetone. Gram Safranin Solution: Dissolve 2.5 g of safranin O in 100 ml of 95 % ethanol to make a stock solution. Working solution is obtained by diluting one part of the stock solution with five parts of water.

Do mycobacteria have mycolic acid?

Mycolic acids are unique long chain fatty acids found in the lipid‐rich cell walls of mycobacteria including the tubercle bacillus M ycobacterium tuberculosis. Essential for viability and virulence, enzymes involved in the biosynthesis of mycolic acids represent novel targets for drug development.