Last to update on June 18th, 2021The straightforward stain deserve to be provided as a quick and also easy way to determine cell shape, size and arrangements of bacteria. True come its name, the simple stain is a very an easy staining procedure involving a solitary solution the stain. Any basic dye such as methylene blue, safranin, or decision violet can be supplied to shade the bacter cells.These stains will certainly readily give up a hydroxide ion or expropriate a hydrogen ion, which leaves the stain positively charged. Since the surface of most bacterial cells and also cytoplasm is negative charged, this positively charged stains adhere easily to the cabinet surface. After staining, bacterial cell morphology (shape and arrangements) deserve to be appreciated.

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Simple Staining Procedure

Preparation the a smear

Using a sterilized inoculating loop, transfer loopful of liquid suspension include bacteria to a slide (clean grease free microscopic slide) or move an isolated nest from a society plate to a slide v a water drop.Disperse the bacteria top top the loop in the fall of water ~ above the slide and also spread the drop over an area the dimension of a dime. It have to be a thin, even smear.Allow the smear to dried thoroughly.Heat-fix the smear cautiously by passing the underside of the slide with the burner flame two or three times. It fixes the cell in the slide. Perform not overheat the slide together it will distort the bacterial cells.


Cover the smear with methylene blue and enable the dye to remain in the smear for about one minute (Staining time is not critical here; somewhere in between 30 seconds to 2 minute should offer you an acceptable stain, the much longer you leave the dye in it, the darker will be the stain).Using distilled water wash bottle, gently to wash off the overabundance methylene blue native the slide by directing a gentle stream of water over the surface of the slide.Wash off any stain that gained on the bottom the the slide together well.Saturate the smear again but this time with Iodine. Iodine will set the stainWash of any kind of excess iodine through gently to run tap water. To wash thoroughly. (You may not acquire a mention of step 4 and 5 in some textbooks)Wipe the earlier of the slide and blot the stained surface ar with bibulous record or with a file towel.Place the stained smear ~ above the microscope stage smear next up and also focus the smear utilizing the 10X objective.Choose an area that the smear in i m sorry the cells space well spread in a monolayer. Center the area to be studied, use immersion oil straight to the smear, and also focus the smear under oil through the 100X objective.
Left: Cocci in Cluster; Right: Bacilli (Image source:


The bacter cells typically stain uniformly and the color of the cell relies on the kind of dye used. If methyene blue is used, part granules in the internal of the cells of some bacteria may appear more deeply stained 보다 the rest of the cell, which is because of presence of various chemical substances.


Diagnostic microbiology laboratory usually does not perform basic staining methods. Differential staining such together Gram Staining and AFB Staining are frequently used come identify and also differentiate the bacter isolates. Basic staining can be helpful in the adhering to circumstances.To differentiate bacteria native yeast cells: when endocervical swab culture is done in blood agar both Staphylococcus spp and also yeast cell may offer similar-looking swarms in Blood agar (a typical error for a new technologist or microbiologist with less experience). Performing the wet mount method or simple staining from the isolate have the right to be helpful.

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To presumptively recognize the bacter isolateDue come their common presence, Bacillus spp may present as a contaminant in the culture plates. In some scenarios (e.g. Expansion in Blood Agar however no expansion in MacConkey Agar), identify the shape of the bacteria (rod or cocci) may assist to get rid of the isolate as feasible contaminants (e.g., Bacillus spp) or further process as a potential microorganism (cocci).