How does gram stain help identify bacteria

After they have collected the sample, they will send it to a laboratory for testing. A technician will use a special staining technique to make it easier to see bacteria under a microscope.

If your gram stain results are negative, it means no bacteria were found in your sample. Because of the staining technique used, gram-positive bacteria will appear purple under a microscope and gram-negative bacteria will appear pink. The shape, size, and quantity of bacteria present will also provide information about your infection. There are no known risks involved in performing a gram stain on a sample of urine, stool, or mucus. If your doctor orders a gram stain on a sample of blood or tissue, some risks are involved in collecting the sample.

For example, you may experience bruising, bleeding, or infection as a result of a blood draw. Ask your doctor for more information about the specific risks involved in your case. The main benefit of a gram stain is that it helps your doctor learn if you have a bacterial infection, and it determines what type of bacteria are causing it. This can help your doctor determine an effective treatment plan. Gram-positive bacteria are bacteria with thick cell walls.

In a Gram stain test, these organisms yield a positive result. Muscular dystrophy is a group of inherited diseases that damage and weaken your muscles over time. This damage and weakness is due to the lack of a…. Boils are caused by bacteria building up in a hair follicle and pushing up to the surface of the skin.

Recurring boils happen for a number of reasons…. Certain E. Learn about other bacteria and parasites like pinworms and how to prevent…. Shigellosis is a bacterial infection that affects the digestive system. Painstakingly put together in a simple language. All enterobcteriaceae are gram negative bacteria but not all gram negative are enterobcteriaceae to distinguish the enterobcteriaceae you have to do oxidase test because enterobcteriaceae are oxidase negative bacteria.

But if i may ask, which step in Gram staining tech can be omited without affecting the final result? Mr Len artifacts results from poor methods of rinsing of slides. Beside, what is the color of safranin? More of a controlled decolorization. If Gram positive organisms have such complex cell wall that could defy decolorisation,why then is a mordant used?

Moreover, the test procedure is performed to differentiate between the two groups of bacteria. Save my name and email in this browser for the next time I comment. Principle of Gram Staining When the bacteria is stained with primary stain Crystal Violet and fixed by the mordant, some of the bacteria are able to retain the primary stain and some are decolorized by alcohol.

Prepare the smear of suspension on the clean slide with a loopful of sample. Air dry and heat fix Crystal Violet was poured and kept for about 30 seconds to 1 minutes and rinse with water. Add safranin for about 1 minute and wash with water. Alternatively, Gram negative bacteria stain red, which is attributed to a thinner peptidoglycan wall, which does not retain the crystal violet during the decoloring process.

Gram staining involves three processes: staining with a water-soluble dye called crystal violet, decolorization, and counterstaining, usually with safanin.

Due to differences in the thickness of a peptidoglycan layer in the cell membrane between Gram positive and Gram negative bacteria, Gram positive bacteria with a thicker peptidoglycan layer retain crystal violet stain during the decolorization process, while Gram negative bacteria lose the crystal violet stain and are instead stained by the safranin in the final staining process.

The process involves three steps:.