What is Gram stain in medical terms?

Gram’s stain (grămz) A staining technique used to classify bacteria in which a bacterial specimen is first stained with crystal violet, then treated with an iodine solution, decolorized with alcohol, and counterstained with safranin.

What is the process of Gram staining?

The performance of the Gram Stain on any sample requires four basic steps that include applying a primary stain (crystal violet) to a heat-fixed smear, followed by the addition of a mordant (Gram’s Iodine), rapid decolorization with alcohol, acetone, or a mixture of alcohol and acetone and lastly, counterstaining with …

What Gram stain is Streptococcus?

Streptococci are Gram-positive, nonmotile, nonsporeforming, catalase-negative cocci that occur in pairs or chains. Older cultures may lose their Gram-positive character.

What is difference between Gram-positive and negative?

Gram positive bacteria have a thick peptidoglycan layer and no outer lipid membrane whilst Gram negative bacteria have a thin peptidoglycan layer and have an outer lipid membrane.

What are the 2 types of Gram stain?

Gram staining is a bacteriological laboratory technique used to differentiate bacterial species into two large groups (gram-positive and gram-negative) based on the physical properties of their cell walls.

Why is Gram staining important in the medical field?

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.

What is purpose of staining?

The Simple Stain Living bacteria are almost colorless, and do not present sufficient contrast with the water in which they are suspended to be clearly visible. The purpose of staining is to increase the contrast between the organisms and the background so that they are more readily seen in the light microscope.

Why Iodine is used in Gram staining?

Gram’s iodine is used in Gram staining procedure to differentiate gram positive and gram negative organisms. Gram’s iodine acts as a mordant that causes the crystal violet to penetrate and adhere to the gram –positive organisms.

Why is it called Gram stain?

The name comes from the Danish bacteriologist Hans Christian Gram, who developed the technique. Gram staining differentiates bacteria by the chemical and physical properties of their cell walls. Gram-negative cells have a thinner peptidoglycan layer that allows the crystal violet to wash out on addition of ethanol.

What does a gram stain test for?

A Gram stain is a test that checks for bacteria at the site of a suspected infection such as the throat, lungs, genitals, or in skin wounds. Gram stains may also be used to check for bacteria in certain body fluids, such as blood or urine.

What are the results of Gram staining?

Gram staining of the peptidoglycan layer (which is the cell wall) with a chemical called crystal violet results in purple coloration of the gram-positive bacteria. Addition of acetone or alcohol dehydrates the bacteria, causing it to retain the purple color.

What is the purpose of a Gram stain?

An essential test for the rapid presumptive diagnosis of infectious agent

What are the principles of Gram staining?

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. The cell walls of gram positive bacteria have a thick layer of protein-sugar complexes called peptidoglycan and lipid content is low.

What is the primary stain in Gram staining?

The primary stain is used in Gram staining to detect Gram-positive bacteria. The primary stain is a crystal violet color. When a bacteria is Gram-negative, it loses the primary stain and takes on the secondary stain of safranin.