What are the steps 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 is Gram staining PPT?
1. Gram staining is a method of differentiating bacterial species into two large groups(Gram-positive and Gram-negative). The Gram staining is almost always the first step in the identification of bacteria.
What is Gram staining PDF?
Gram staining is an empirical method of differentiating bacterial species into two large groups (Gram-positive and Gram-negative) based on the chemical and physical properties of their cell walls.
What are the methods of staining?
Types of Staining Techniques
| Sr. No. | Staining Technique |
|---|---|
| 1. | Simple (Monochrome) |
| 2. | Negative (Relief) |
| 3 | Gram |
| 4 | Acid fast (Ziehl-Neelsen technique) |
How many types of stain are there?
Seven Types
What are the three basic stains?
Basic stains, such as methylene blue, Gram safranin, or Gram crystal violet are useful for staining most bacteria.
What is the purpose of staining?
The main reason you stain a specimen before putting it under the microscope is to get a better look at it, but staining does much more than simply highlight the outlines of cells. Some stains can penetrate cell walls and highlight cell components, and this can help scientists visualize metabolic processes.
Why are the cells stained in pink?
The acidic portion of the stain unites with the basic components of the cells such as hemoglobin, and thus they are referred to as eosinophilic and are stained pink or red. The acidic components of the cell, such as the nucleic acids on the other hand take the basic dye and stain blue or purple.
What is the purpose of staining bacteria?
Introduction: Gram staining is a method commonly used to determine the chemical make up of the cell wall of bacteria. The cell wall can stain either positive or negative, depending on its chemistry.
Why do we stain bacterial smear?
Because bacteria are, for the most part, transparent, we use stains to give them color for microscopic observation. Making a bacterial smear prepares the bacteria to be stained and a simple stain is a quick and easy way to observe bacteria.
What are two reasons for staining bacteria?
The most basic reason that cells are stained is to enhance visualization of the cell or certain cellular components under a microscope. Cells may also be stained to highlight metabolic processes or to differentiate between live and dead cells in a sample.
What is the difference between positive staining and negative staining?
In most cases, it is preferable to use a positive stain, a dye that will be absorbed by the cells or organisms being observed, adding color to objects of interest to make them stand out against the background. Negative staining produces an outline or silhouette of the organisms against a colorful background (Figure 2).
Why is iodine used in Gram staining?
Exposing gram negative cells to the decolorizer dissolves the lipids in the cell walls, which allows the crystal violet-iodine complex to leach out of the cells. This allows the cells to subsequently be stained with safranin.
What color is gram negative bacteria?
Red
What is the difference between Gram positive and Gram negative bacteria?
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.
Why is it important to know Gram positive or negative?
If bacteria are present, this test can also help your doctor learn if the bacteria are gram negative or gram positive. The difference between gram-negative and gram-positive bacteria can affect their recommended treatment plan. Gram stains can be performed on various types of specimens, including: blood.
Is Gram positive or negative more dangerous?
Gram-positive bacteria cause tremendous problems and are the focus of many eradication efforts, but meanwhile, Gram-negative bacteria have been developing dangerous resistance and are therefore classified by the CDC as a more serious threat.
What antibiotic is used to treat gram-positive cocci?
Most infections due to Gram-positive organisms can be treated with quite a small number of antibiotics. Penicillin, cloxacillin, and erythromycin should be enough to cover 90 per cent of Gram-positive infections.
What antibiotics work against Gram-positive bacteria?
Antibiotics for Gram-Positive Bacterial Infection: Vancomycin, Teicoplanin, Quinupristin/Dalfopristin, Oxazolidinones, Daptomycin, Telavancin, and Ceftaroline.
Do Gram-positive bacteria cause UTI?
Gram-positive bacteria are a common cause of urinary tract infection (UTI), particularly among individuals who are elderly, pregnant, or who have other risk factors for UTI.
Which bacteria are gram-positive rods?
There are five medically important genera of gram-positive rods: Bacillus, Clostridium, Corynebacterium, Listeria, and Gardnerella. Bacillus and Clostridium form spores, whereas Corynebacterium, Listeria, and Gardnerella do not.
What is the structure of Gram-positive bacteria?
Gram-positive bacteria are surrounded by many layers of peptidoglycan (PG), which form a protective shell that is 30–100 nm thick (Silhavy et al. 2010). The PG layers are covalently modified with carbohydrate polymers including wall teichoic acids (WTAs) or functionally related anionic glycopolymers as well as CPS.
How do you read a urine culture report?
For a urine culture, the urine is given several days to allow the bacteria, if present, to grow. The sample is then examined under a microscope. If your urine shows signs of bacteria or other organisms, you will receive a positive result. If few bacteria or organisms appear, you will receive a negative test result.