This method of staining can be
trace back to 1884, which a man called Christian Gram explained this method
that is very important staining in routine bacteriology today. In the process
of his explanation, he group organism into two, which is Gram positive and Gram
negative, the grouping base on either the organism can be decolorized with
acetone, alcohol, or aniline oil after staining with dye i.e. methyl violet,
crystal violet, or gentian violet and been with iodine. On this method those
microorganism bacteria that resist change of color after been stain with dye,
take the primary color stain such as methyl or crystal violet, they are called
Gram positive, while those organism that resist primary color and take the dye
color such as safranin they are called Gram negative. Bellow table are group of
gram positive and gram negative bacteria.
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Gram positive
Gram negative
Bacillus
Coliforms
Clostridia
Neisseriae
Mycobacteria
Vibrios
Staphylococcus
Haemophilus Spp
Pneumococci
Spirochaete
Corynebacteria
Shigellae
Streptococcus
Salmonellae
This method has been extensively
studied but seem so difficult to understand, however others method exist which
aid in examination of those organism.
However there are basic
differences between those groups of organism in the cell wall composition. Therefore
after gram staining, another method is employed for the examination of some
bacteria because not all of these bacteria can be demonstrated by using only
gram staining procedure i.e. such as Bacillus spp, can only be examine with the
used of staining called Acid-Fast Bacilli. i.e. Ziehl-Neelsen stain, Auramine
Stain.
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