The identification of Mycobacteria with rhodamine-auramine is due to the affinity of the mycolic acid in the cell walls for the fluorchromes. These dyes will bind to the Mycobacteria, which appear bright yellow or orange against a greenish background. The potassium permanganate helps prevent non-specific fluorescence. All acid-fast organisms will be stained by rhodamine-auramine, including the sporozoan parasites. Slides stained with rhodamine-auramine may be restained with Ziehl-Neelsen or Kinyoun stain directly, as long as the oil has been removed. This provides a convenient method of confirming and differentiating morphology of positive slides with the traditional stains.
|AAD-8oz||Fluorescent Decolorizer||8 oz.|
|AAD-1gl||Fluorescent Decolorizer||1 gallon|
|PPC-1-8oz||Potassium Permanganate||8 oz.|
|PPC-1-1gl||Potassium Permanganate||1 gallon|
Organisms being stained by an acid fast method are usually taken from a solid or liquid medium on (in) which they have been cultured from their original source (e.g. wounds, throat, swabs, sputum, etc.). An aqueous suspension is made, in the case of the solid medium, by taking a small amount of the material and suspending it in a drop of distilled water on a microscope slide. Care should be taken not to make the smear too thick. In the case of a liquid medium, a drop is used directly from the culture container. However, due to the solids from the medium, this method is not always satisfactory. The suspension made by either method is air dried, then "fixed" by passing rapidly through a Bunsen burner flame two or three times. Allow the smear to cool before staining.
Note: Staining times may vary to suit the individual.