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Related Flashcards
Cards In This Set
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What type of Stain is the Acid Fast Stain?
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Differential, it differentials between acid fast and non acid fast bacteria
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What 2 Genera belong to Acid Fast?
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Mycobacterium (TB and Leprosy) and Nocardia
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What type of cell wall do Acid Fast cells have?
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Waxy, made of Mycolic Acid
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What does the Mycolic Acid make the organism resistant to?
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Dessication and disinfectants.
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What are the 2 means to stain Acid-Fast bacteria?
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Ziehl-Neelsen and Kinyoun method
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What does the Ziehl-Neelsen method use?
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Steaming water bath to facilitate staining
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What does the Kinyoun method use?
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Called "the cold method" because it does not require steam
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Explain the Ziehl-Neelsen technique
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You steam heat fixed slides over boiling water with the Primary Stain, Carbol Fuchsin. Heating "melts" or increases the fluidity of the waxy cell wall and permits the penetration of the primary stain. When the slide cools, the waxy wall firms up and loses it's fluidity trapping the stain in the cell. Smears are then decolorized with Acid-Alcohol. Cells that retain teh Primary stain after decolorization are Acid-Fast, bright red Fuchsia color. Then the slide is counterstained with Methylene Blue to dye the Non-Acid fast cells. Non-Acid Fast will appear Blue
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How is the Kinyoun Acid Fast method different from the Ziehl-Neelsen method?
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Steps are the same, Carbol Fuschin, Acid-Alcohol and Methylene Blue but does not require the slide to be steamed
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In the Kinyoun method, what permits the staining of cells at benchtop temperatures?
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The primary stain reagent contains higher concentrations of phenol and basic Fuchsin stain thatn in the Ziehl-Neelsen reagent
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Why do you place a paper towel over the smear?
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To decrease spattering and to prevent crystals from forming directly on the smear when steaming
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How long must you steam the Carbol Fuchsin in the Ziehl-Neelsen method
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5 minutes so that the dye will take
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What do you do during staining so that the slide does not dry out?
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Reapply stain as it evaporates
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What should you do before Decolorizing?
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Let the slide cool
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