35113 Final: Epidemiology & Microbiology
Document Summary
In the micro-organism world we need to allocate a variety of staining tests, biochemical tests and agar environments to enable us to identify and distinguish the bacteria from one another. The gram stain is used to differentiate between gram negative and gram positive bacteria. Essentially the if the membrane is mostly composed of peptidoglycan the crystal violet stain will retain within the membrane with the help of iodine. If not, it will simply be washed away and carbol fuschin will be used last to stain as gram negative. From the gram stain we are able to differentiate the unknown (assuming it"s a pure culture) into two categories as either being gram positive (purple crystal violet) or gram negative (pink- carbol fuschin: capsule stain. Some bacterium have a capsule or slime layer which is a tough outer- membrane mostly composed of polysaccharides. India ink or nigrosin to stain the capsule of the bacterium.
