The gram stain permits the separation of all bacterial species into two large groups, those which retain the primary dye (gram-positive), and those which lose the primary dye and take the color of the secondary dye (gram-negative). The mechanism of gram stain is based on the distinctive chemistry and physical properties of the cell wall, possibly the lipid content. However, the exact mechanism of gram stain is still unknown.
|512A-8oz||Crystal Violet||8 oz.|
|512A-1gl||Crystal Violet||1 gallon|
|604A-8oz||Grams Iodine||8 oz.|
|604A-1gl||Grams Iodine||1 gallon|
|605A-8oz||Stabilized Gram's Iodine||8 oz.|
|605A-1gl||Stabilized Gram's Iodine||1 gallon|
|304A-8oz||Grams Decolorizer||8 oz.|
|304A-1gl||Grams Decolorizer||1 gallon|
*The safranin counter stain may be substituted with basic fuchsin counter stain catalog # 435A for better Anaerobe staining.
Organisms being stained by the gram 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.