1. Compare and contrast the Simple Stain and the Acid Fast Stain. Acid Fast Stai
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1. Compare and contrast the Simple Stain and the Acid Fast Stain. Acid Fast Stain Simple Stain Primary Stain is: Decolorizing reagent is: Color of bacteria after decolorizing Counterstain? (Yes or No) and Name of stain if one is used. Is this a differential stain? 2. Compare and contrast the Acid Fast Stain and the Gram Stain. Gram Stain Acid Fast Stain Primary Stain (Name Reagent) Decolorizing Reagent is: Color of bacteria after decolorizing Counterstain? (Yes or No) and Name of stain if one is used Is this a differential stain?Explanation / Answer
Q1) Compare and contrast the simple stain with Acid fast stain
Simple stain- In simple stain a single stain is used, it might be Methylene Blue, Safranin or Crystal violet. Here basic dyes are used they make the cells dark enough to see in a light background. Basic dyes are positively charged stains and they get attached to the negatively charged bacterial cell wall, colouring the cell wall of bacteria. Here Iodine is used to saturate the smear and it sets the stain.
No decolourizing agent is used.
No counterstain is used
It is not a differential stain, it is used to compare shape size and arrangement of Bacteria.
In Acid fast stain- The primary stain is - Carbolfuschin
The decolourizing agent is - Acid alcohol
In case of positive Acid fast bacteria the color is Red, in case of negative or non-acid fast bacteria it is colorless.
Counterstain used here is Methylene blue, if positive it is Red if negative it is Blue, yes it is used as a differential stain. It uses more than one chemical stain,
It is used to differentiate between Acid fast and non-acid fast bacteria, Mycobacterium and the Nocardia species are called acid-fast because during an acid-fast staining procedure, the primary dye carbol fuchsin remains in spite of the process of decolorization by the powerful solvent acid-alcohol. All other genera of bacteria are nonacid-fast. The acid-fast bacteria have lipoidal mycolic acid in their cell walls. It is considered that mycolic acid prevents acid-alcohol from decolorizing protoplasm.
Q2) Compare and contrast between Acid fast stain and Gram stain.
Acid fast stain:-
Primary stain- carbolfuschin
Decolourizing agent- Acid alcohol
Color of bacteria after decolorization- In case of positive it is RED and in negative it is BLUE
Counterstain used is - Methylene blue
Is this a differential stain- Yes it differentiates between Acid fast and non-acid fast bacteria.
Gram stain-
Primary stain used- Crystal violet is used as primary stain.
Decolourizing reagent- Ethyl alcohol/ acetone
color of bacteria after decolourization- In case of positive or gram positive color is Blue, in case of gram negative it is colorless, ethyl alcohol extracts the blue-dye complex from the lipid rich thin cell wall of gram-ve bacteria making it colorless.
Counterstain used is - Safranin is used,after use of safranin the red dye it makes the colorless Gm-ve bacteria into Red/Pink, and Gm + ve bacteria remains Blue.
Yes it is a differential stain, it is used to distinguish between Gram + ve and Gram -Ve bacteria, based on their cell wall. Gm+ve cellwall contains thick layer of peptidoglycan having teichoic acid cross linking which prevents decolourization.
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