This makes the Gram stain a valuable diagnostic tool for a medical clinic or lab. While the stain may not definitely identify bacteria, often knowing whether they are gram-positive or gram-negative is sufficient for prescribing an effective antibiotic. Limitations of the Technique Some bacteria may be gram-variable or gram-indeterminate.
How is Gram stain helpful in medicine?
A Gram stain is most often used to find out if you have a bacterial infection. If you do, the test will show if your infection is Gram-positive or Gram-negative. A Gram stain may also be used to diagnose fungal infections.
How does Gram staining help a doctor prescribe treatment for a bacterial infection?
A Gram stain is a laboratory test that checks for bacteria at the site of a suspected infection or in certain bodily fluids. A medical laboratory scientist processes the Gram stain, which gives relatively quick results, so healthcare providers can know if bacteria are present, and, if so, the general type(s).
Why are gram bacteria easier to treat with antibiotics?
Gram-positive bacteria, those species with peptidoglycan outer layers, are easier to kill - their thick peptidoglycan layer absorbs antibiotics and cleaning products easily. In contrast, their many-membraned cousins resist this intrusion with their multi-layered structure.
Why is the Gram stain useful in classifying bacteria?
The Gram stain is the most important staining procedure in microbiology. It is used to differentiate between gram positive organisms and gram negative organisms. Hence, it is a differential stain. Gram negative and gram positive organisms are distinguished from each other by differences in their cell walls.
How is a Gram stain useful for a nurse?
You may have this test to diagnose an infection caused by bacteria. It can also identify the type of bacteria causing the infection. This test can help find the cause of various health problems, including: Intestinal infection or illness.
How do antibiotics work against Gram-negative bacteria?
Antibiotics may inhibit bacterial growth or may kill bacteria by inhibiting cell wall synthesis or protein synthesis. The amount of endotoxin released during antibiotic action has been found to be clinically important.
Why do some antibiotics only work on Gram-negative bacteria?
1). Many antibiotics, such as vancomycin, which like β-lactam antibiotics targets the cell wall peptidoglycan, are ineffective against Gram-negative bacteria, simply because they have chemical properties that do not allow them to utilize these pathways to effectively penetrate the outer membrane.
Why do some antibiotics only work on Gram-negative bacteria or only Gram-positive bacteria?
Any alteration in the outer membrane by Gram-negative bacteria like changing the hydrophobic properties or mutations in porins and other factors, can create resistance. Gram-positive bacteria lack this important layer, which makes Gram-negative bacteria more resistant to antibiotics than Gram-positive ones [5,6,7].
Why is gram staining important?
In microbiology, gram staining is an important test used because it can determine the presence of bacteria in a sample, as well as differentiate between the two distinct bacteria species, which are gram-posi tive and gram-negative bacteria. This test also is especially important in medicine because the identification of the specific pathogen can ...
What is the color of gram positive bacteria?
After staining, bacteria differentiation is possible because gram-positive bacteria have a purple color while gram-negative bacteria have a pink color when viewed under a light microscope.
Why is Gram stain important?
Because the bacteria are colored, not only is their Gram stain group identified, but their shape, size, and clumping pattern may be observed . This makes the Gram stain a valuable diagnostic tool for a medical clinic or lab.
How does Gram stain work?
How the Gram Stain Works 1 The primary stain ( crystal violet) binds to peptidoglycan, coloring cells purple. Both gram-positive and gram-negative cells have peptidoglycan in their cell walls, so initially, all bacteria stain violet. 2 Gram's iodine ( iodine and potassium iodide) is applied as a mordant or fixative. Gram-positive cells form a crystal violet-iodine complex. 3 Alcohol or acetone is used to decolorize the cells. Gram-negative bacteria have much less peptidoglycan in their cell walls, so this step essentially renders them colorless, while only some of the color is removed from gram-positive cells, which have more peptidoglycan (60-90% of the cell wall). The thick cell wall of gram-positive cells is dehydrated by the decolorizing step, causing them to shrink and trapping the stain-iodine complex inside. 4 After the decolorizing step, a counterstain is applied (usually safranin, but sometimes fuchsine) to color the bacteria pink. Both gram-positive and gram-negative bacteria pick up the pink stain, but it is not visible over the darker purple of the gram-positive bacteria. If the staining procedure is performed correctly, gram-positive bacteria will be purple, while gram-negative bacteria will be pink.
What is Gram staining?
The Gram stain is a differential method of staining used to assign bacteria to one of two groups (gram-positive and gram-negative) based on the properties of their cell walls. It is also known as Gram staining or Gram's method.
What is the primary stain for Gram staining?
The Gram stain involves staining bacteria, fixing the color with a mordant, decolorizing the cells, and applying a counterstain. The primary stain ( crystal violet) binds to peptidoglycan, coloring cells purple. Both gram-positive and gram-negative ...
What is the primary stain for Gram positive bacteria?
The primary stain ( crystal violet) binds to peptidoglycan, coloring cells purple. Both gram-positive and gram-negative cells have peptidoglycan in their cell walls, so initially, all bacteria stain violet. Gram's iodine ( iodine and potassium iodide) is applied as a mordant or fixative. Gram-positive cells form a crystal violet-iodine complex.
What is the difference between Gram positive and Gram negative cells?
Gram-positive cells form a crystal violet-iodine complex. Alcohol or acetone is used to decolorize the cells. Gram-negative bacteria have much less peptidoglycan in their cell walls, so this step essentially renders them colorless, while only some of the color is removed from gram-positive cells, which have more peptidoglycan ...
Do Gram negative cells have peptidoglycans?
Gram-negative bacteria have much less peptidoglycan in their cell walls, so this step essentially renders them colorless, while only some of the color is removed from gram-positive cells, which have more peptidoglycan (60-90% of the cell wall). The thick cell wall of gram-positive cells is dehydrated by the decolorizing step, ...
What is a Gram stain?
A Gram stain is a test that checks for bacteria at the site of a suspected infection or in certain body fluids, such as blood or urine. These sites include the throat, lungs, and genitals, and in skin wounds. There are two main categories of bacterial infections: Gram-positive and Gram-negative. The categories are diagnosed based on the how ...
What happens when a stain is a Gram positive?
When the stain combines with bacteria in a sample, the bacteria will either stay purple or turn pink or red. If the bacteria stays purple, they are Gram-positive. If the bacteria turns pink or red, they are Gram-negative. The two categories cause different types of infections: Gram-positive infections include methicillin-resistant Staphylococcus ...
Is it safe to have a blood test if you have a swab?
There is no risk to having a swab, sputum, or urine test. There is very little risk to having a blood test. You may have slight pain or bruising at the spot where the needle was put in, but most symptoms go away quickly.
What does it mean when there are no bacteria in a slide?
A laboratory professional will examine the slide under a microscope. If no bacteria were found, it means you probably don't have a bacterial infection or there weren't enough bacteria in the sample. If bacteria were found, it will have certain qualities may provide important information about your infection:
What is the shape of a bacteria?
Most bacteria are either round (known as cocci) or rod-shaped (known as bacilli). The shape can provide more information about the type of infection you have.
What are the two main categories of bacterial infections?
These sites include the throat, lungs, and genitals, and in skin wounds. There are two main categories of bacterial infections: Gram-positive and Gram-negative. The categories are diagnosed based on the how the bacteria reacts to the Gram stain. A Gram stain is colored purple. When the stain combines with bacteria in a sample, ...
Why do we use Gram stain?
1. It gives quick results when examining infections. In most cases, Gram stains are performed on biopsy or bodily fluids when infection is suspected, and they yield results much more quickly than other methods, such as culturing.
Is Gram stain a good technique for microbiology?
1. It has significant limitations when used for environmental microbiology. The Gram stain is definitely not an infallible technique for identification, diagnosis or phylogeny, and it faces extreme limitations when used in environmental microbiology. While it is used primarily for making a preliminary morphologic identification or ...
What is Gram staining?
Gram staining, which is also referred to as the Gram’s method, is a scientific technique of staining that is used to differentiate the species of bacteria into 2 main groups, namely the gram-positive and the gram-negative bacteria. The differences between these groups of bacteria are considered to be important in determining appropriate treatments ...
Can a Gram stain be used to determine if a virus is present?
In some cases, it would not be clear whether an infection is caused by bacteria, fungi or viruses, and these kinds of infection would be treated in different ways. Now, a Gram stain will let physicians determine whether a certain type of bacteria is causing the infection and what type of microorganism is present.
What does a Gram stain test show?
Now, a Gram stain will let physicians determine whether a certain type of bacteria is causing the infection and what type of microorganism is present . This is why any person who is suspected to have bacterial infection or actually is having one is a candidate for a Gram staining test.
What are the disadvantages of Gram staining?
List of Disadvantages of Gram Staining. 1. It has significant limitations when used for environmental microbiology. The Gram stain is definitely not an infallible technique for identification, diagnosis or phylogeny, and it faces extreme limitations when used in environmental microbiology. While it is used primarily for making a preliminary ...
Is Gram stain an infallible technique?
It has significant limitations when used for environmental microbiology. The Gram stain is definitely not an infallible technique for identification, diagnosis or phylogeny, and it faces extreme limitations when used in environmental microbiology.
Why do you need a gram stain?
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.
Can a doctor order a Gram stain?
Your doctor may order a gram stain if you have symptoms of an infection. They may not know if the infection is bacterial, viral, fungal, or parasitic. These types of infections are typically treated differently. Different types of bacterial infections may also require different treatments. Your doctor can use a gram stain to learn ...
What does it mean when a gram stain is negative?
If your gram stain results are negative, it means no bacteria were found in your sample. If they’re positive, it means bacteria were present. Because of the staining technique used, gram-positive bacteria will appear purple under a microscope and gram-negative bacteria will appear pink.
What does it mean when a gram positive is pink?
If they’re positive, it means bacteria were present. 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.
Why do Gram positive bacteria look purple?
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.
Is it safe to get a gram stain on your urine?
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.
What to do if your doctor suspects you have an infection?
If your doctor suspects you have an infection, they may order a culture and gram stain to check for bacteria. If bacteria are present, this test can also help your doctor learn if the bacteria are gram negative or gram positive.
Why is gram staining important?
Gram staining procedure is used to determine if bacteria are gram-positive or gram-negative. This is usually the first step in the process of identifying bacteria that are present in cultures. This procedure is important in giving a clue to the diagnosis in people with infectious diseases. It also helps in the estimation of the total count ...
When to use Gram staining?
When to Apply Gram Staining. Gram staining procedure is used to determine if bacteria are gram-positive or gram-negative. This is usually the first step in the process of identifying bacteria that are present in cultures. This procedure is important in giving a clue to the diagnosis in people with infectious diseases.
How to get gram stain out of a smear?
While holding your slide at one end (smear-side up), pass the slide through flame from a Bunsen burner, 2-3 times. Avoid over-heating to prevent coagulation and distortion of the proteins in the specimen. Now you are ready for the gram staining procedure.
Is alcohol gram positive or negative?
However, when washed with alcohol, bacteria with thicker cell walls containing peptidoglycans tend to retain these molecules and remain violet in color, thus they are called Gram-positive bacteria. On the other hand, the dye is washed away from bacteria with thinner cell walls, and these are considered gram-negative.
How to make a bacterial suspension?
To make a bacterial suspension in broth, use a cooled sterile loop to place a small amount of broth culture on your slide. Using a circular motion spread the broth with the inoculating loop until it is about 1 cm in diameter. Do not spread excessively to prevent disruption of the cellular arrangement.
How to differentiate 2 bacteria groups?
Experts use gram staining procedure as one of the techniques to differentiate 2 bacteria groups according to their cell wall characteristics. It involves using a dye to see which bacteria retain either color—violet or red in their cell walls.
What is Gram staining?
Gram staining is initially established by the physician Hans Christian Gram, which was from Denmark. He help to distinguish Klebsiella pneumonia to pneumococci. In short, the process of gram staining comprises the use of a solution of Gram iodine or Potassium iodide to the cells which are use to stain before with Crystal violet or Gentian violet.
Who is the gram staining scientist?
Last Modified on April 19, 2020 | No comments. Gram staining is initially established by the physician Hans Christian Gram, which was from Denmark. He help to distinguish Klebsiella pneumonia to pneumococci. In short, the process of gram staining comprises the use of a solution of Gram iodine or Potassium iodide to the cells which are use ...
What is the difference between Gram positive and Gram negative bacteria?
The variance among Gram positive bacteria and Gram negative bacteria is in their permeability of the cell wall, purple color dye Gram Iodine, when treat with the decolorizing reagent. Though Gram positive keep purple iodine stain later they treat with the decolorizing solution, Gram negative does not keep complexes when it is decolorized.
Does Gram negative stain purple?
Though Gram positive keep purple iodine stain later they treat with the decolorizing solution, Gram negative does not keep complexes when it is decolorized. To see gram negative, 1 st they are decolorized, a red color counter stain/dye, Safranin is use later decolorization solution treatment.
What is Gram positive bacteria?
Bacteria retain the crystal violet and gram iodine mixtures complexes after the wash in 95% ethanol solution in purple color and are named as Gram positive Bacteria, those which miss these complexes of solution are red in color by counter stain the safranin or 10% fuchsine are named as Gram negative Bacteria. Gram Staining Results.
What is Gram positive?
Gram positive organisms are dehydrated by alcohol, they have very dense cell wall containing of many coatings of peptido-glycan. This creates the pores/holes in the cell wall to near, avoiding the insoluble crystal violet + gram iodine complexes from evasion.
How to make Gram positive and Gram negative cells purple?
Both Gram-positive and Gram-negative cells will be stained purple by the crystal violet dye. Add several drops of iodine to the smear and allow it to sit for 1 minute. Rinse the slide with water. Iodine “sets” the crystal violet, so both types of bacteria will remain purple.