The objective of this experiment is to illustrate the differentiation of bacteria in acid-rapid and non-acid quick staining teams. Most bacterial organisms deserve to be stained by either basic or Gram staining procedures. The features displayed between mycobacteria and also other microorganisms are very different because of the visibility of a thick, waxy wall that makes the stain penetration very difficult. Once the stain is penetrated, it is not able to be conveniently rerelocated even through the vigorous acid-alcohol agent, unchoose the 95% ethyl alcohol that is supplied in gram staining. This a very crucial property bereason it is what distinguishes these organisms as acid-fast, versus non- acid-quick, which are easily decolorized by acid alcohol (Cappuccino 81).

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The acid-quick staining uses 3 various reagents which consists of the primary stain, the decolorizing agent, and the counterstain. The main stain being provided is carbolfuchsin which is a dark red stain 5% phenol that is soluble in the lipoidal products. It penetprices a lot of of the cell wall, is retained, and enters the bacteria. Acid-alcohol is supplied as the decolorizing agent, because acid-quick cells will certainly be resistant to decolorization as a result of the fact that the major stain is even more soluble in the cellular waxes than in the decolorizing agent. The final reagent supplied in this process is methylene blue, which is offered to stain previously decolorized cells, and also serves as the counterstain.

Materials and Methods

In completing this experiment, we provided a Bunsen burner, warm plate, 250 ml beaker, inoculating loop, glass slides, bibulous paper, lens paper, staining tray, and also a microscopic lense. We also provided 72-96 hour soy broth culture of M. smegmatis and 18-24 hour society of S. aureus and for our reagents, carbolfuschin, acid-alcohol, and methylene blue. In our smear preparation, we took three glass slides and making use of aseptic method, we ready a bacterial smear of each organism plus a third smear which was a mixture of the two onto the third slide. We then enabled the smears to dry, and also once they we dry we heat addressed them by quickly running then over the flame of the Bunsen burner.

After the smears were entirely dry and heat resolved, we flooded the smears via carbolfuchsin and also put the slide over a beaker on a warm hot plate, and allowed it to steam for 5 minutes. Once the slides were totally cooled, we wamelted them with tap water. Next off, we decolorized them by including the acid alcohol, drop by drop onto the slides until the alcohol was nearly clear with a red tinge, then wamelted it via tap water again. Then we counterstained with methylene blue for two minutes and also wamelted through tap water. Once that component was done, we blotted the slides through bibulous paper and also examined it making use of the microscope under oil immersion.


The acid-quick stain revealed that S. aureus stained blue, which supposed that it was non acid-rapid. S. aureus was circular-shaped and had actually a clustered (almost prefer grapes) arrangement. Antithetically, M. smegmatis stained red, which intended that it was acid quick. M. smegmatis was irregular-shaped and also had a pseudofilamentous arrangement. The mixed culture of S. aureus and also M. smegmatis stained pink and blue.

S. aureus

M. smegmatis

Mixture of M. smegmatis and S. aureus

Resee Questions:

1. Why have to warm or a surface-active agent be provided via application of the primary stain throughout acid-quick staining?

Heat is used in acid-fast staining to drive the carbolfuchsin lipoidal cell wall and right into the cytoplasm. Conversely, a surface-active agent have the right to be provided to mitigate the surconfront tension between cell wall of the bacteria and the stain.

2. What is the particular diagnostic value of this staining procedure?

A certain diagnostic worth of acid-quick staining is its usage to confirm the presence of Mycobacterium tuberculosis is patients suspected of experiencing from pulmonary tuberculosis.

3. Why is the application of heat or a surface-active agent not compelled in the time of the application of the counterstain in acid-rapid staining?

The counter stain is supplied to colorize the non-acid-rapid cells present in the speciguys. These cells perform not have actually the kind of cell wall that needs warmth application for the stain to penetrate.

4. A child presents symptoms suggestive of tuberculosis, namely a respiratory infection via a fertile cough. Microscopic examicountry of the child’s sputum reveals no acid-rapid rods. However before, examicountry of gastric washings reveals the visibility of both acid-rapid and also non-acid rapid bacilli. Do you think the boy has actually energetic tuberculosis? Explain.

It does not appear likely that the kid has actually active tuberculosis since the sputum test is a trusted implies of diagnosis pulmonary tuberculosis. It is recommended that three specimens of sputum be collected from suspect individuals and also analyzed (

Works Cited

Cappuccino, James G. Microbiology: a laboratory manual – 10th ed. Glensee, IL: Pearboy, 2014. Publish.

See more: Don T Compromise Yourself You Re All You Ve Got, Janis Joplin “Tuberculosis.” Ojha Institute of Chest Diseases, 2011. Internet. 5 April 2014.