9 Advantages and Disadvantages of 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 for infections.

Developed in 1884 by Danish physician Hans Christian Gram, this method is considered as the most important procedure in microbiology and is still the cornerstone of bacterial identification and the taxonomic division. Basically, a gram stain is a kind of laboratory or microbiology test that is performed to determine whether bacteria are present on a variety of specimens, which include tissue, blood, sputum and stool. While it is generally seen as having a lot of perks, this procedure also has its own set of drawbacks that is also important to look into. Here are the advantages and disadvantages of Gram staining:

List of Advantages of Gram Staining

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. This is especially important when infection would make a crucial difference in a patient’s prognosis and treatment, such as testing synovial fluid for septic arthritis or cerebrospinal fluid for meningitis.

2. It is simple and cost-effective.
This general stain is observed as the simplest, least expensive and most useful among the quick methods that used extensively in microbiology for the preliminary differentiation, identification and classification of microbiological organisms. The procedure is performed to produce precluding information regarding the type of organisms that are directly present from the clinical specimens or from the growth on culture plates. Unlike some other alternatives, it is cost-effective in identifying the presence of microorganisms in normal, sterile body fluids.

3. It helps with determining appropriate treatments for infection.
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. 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. The doctor would order this along with a culture if an individual is showing symptoms of infection.

4. It allows for various methods of testing.
To be able to perform a Gram stain test, there is a need to have a sample of body tissue or fluid, and the collection methods would vary depending on the types of the sample. For mucus or sputum, a patient is allowed to cough up a sample into a specimen container, and in other cases, a blood sample will be collected using a blood draw.

5. It is basically a key procedure in identifying bacteria.
As mentioned above, this method is a very important step in the preliminary characterization and classification of bacteria, and it is a key procedure in identifying bacteria based upon staining characteristics, which enables the bacteria to be examined with the use of a light microscope. Keep in mind that bacteria, which are present in an unstained smear, will be invisible when you view it using a light microscope, but once stained, their arrangement and morphology will make it able to be observed. Moreover, Gram staining is also an important step in the screening of infectious agents that are found in clinical specimens, such as a patient’s direct smear.

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 morphologic identification or for establishing whether there is a substantial number of bacteria in clinical specimens, this method will not be able to identify bacteria to the species level. For medical conditions in most situations, it is not recommended as the sole method to use for bacterial identification. In laboratories for clinical microbiology, this method is used in combination with other molecular and traditional techniques in identifying bacteria.

2. It has a few side effects.
It is noted that Gram staining has a few side effects that can occur depending on the method used for obtaining samples and the type of samples. While some types of samples, such as stool, would not entail certain side effects, blood samples would lead to side effects, such as bruising, because of the blood draw.

3. It comes with certain types of risks.
Though there are no known risks of performing a Gram stain with some samples such as urine or mucus, one that uses tissue samples will carry a few risks related to the removal of tissue, such as infection or excess bleeding.

4. It might lead to misinterpretation.
During the process of staining, the iodine and crystal violet would form a complex within the heat fixed cell, and in organisms that are gram-negative, this complex would be readily washed out by agents, such as alcohol or acetone, but would appear red as they retain only the counterstain. On the other hand, gram-positive organisms would retain the complex after decolorization and would remain purple. This would result to over-decolorization from the loss of the complex and, eventually, misinterpretation.

Infections caused by bacteria should not be ignored even the symptoms are just mild, and one of the most commonly used methods to do this and find some treatments to address severity and spread is Gram staining. As you can see, ignoring infections can eventually lead to tissue and organ damage. However, based on the advantages and disadvantages listed above, do you think this method is best to use instead of some other alternative techniques to attain similar results?

Author Bio
Natalie Regoli is a child of God, devoted wife, and mother of two boys. She has a Master's Degree in Law from The University of Texas. Natalie has been published in several national journals and has been practicing law for 18 years.