Bacteriology classification of bacteria & select gram ⊕ & gram ⊝ infections

Bacteria Staining  Bacteria may be stained by a variety of dyes, including methylene blue, crystal violet, carbol-fuchsin (red), and safranin (red)  The two most important methods, the Gram and acid-fast techniques use staining, decolorization, and counterstaining in a manner that helps to classify, as well as, stain organism  Gram-positive bacteria stain blue/purple with Gram stain o This is retained when washed with ethanol and acetone  Gram-negative bacteria do not retain Gram stain when washed with ethanol and acetone o Counterstain results in pink/red color Marc Imhotep Cray, M.D.