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Biolab

Introduction

In bacteriology, stain is probably the most important and useful method to differentiate types of bacteria. There are three different staining processes will be performed, which are gram staining, acid-fast stain and spore stain
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During the gram staining, bacteria are divided into gram positive and negative or distinguish what type of organisms they are.

There are three steps for gram staining, first step is done by using primary stain of crystal violet, and this application is able to stain bacterial cells. Second step is to wash stained smear with ethyl alcohol. Third step is to stain nuclear that is in the cell by using safranin. Lastly to check if bacteria are whether positive or negative, checking color changes would be the most efficient way. If bacteria are gram positive, the color stays in purple color which is stained from crystal violet, which means alcohol was not able to decolorize this certain bacteria. On the other hand, if bacteria appear to be gram negative, bacteria gets decolorized by alcohol and stained by safranin solution and becomes red or pink color.

The bacteria which have waxy cell walls are stained by the special staining procedures. The acid-fast stain involves with three staining solutions: Modification Kinyoun carbolfuchsin stain, acid-alcohol decolorizing solution and Loffler’s methylene blue counter stain. First, the bacteria are stained with the modification Kinyoun carbolfuchsin stain. By using this stain, the lipid-rich material of the bacterial cell wall is able to dye. However, this can be done only if the smear is heated. The next step is to decolorize the stain by acid-alcohol decolorizing solution. The microbes except for the acid-fast are decolorized. The non-acid fast microbes are counterstained with methylene blue agent. As a result, the experimenter will observe the not decolorized acid-fast organisms which appear red and decolorized non-acid-fast organisms which appear as blue.

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