Gram Staining

Gram Staining: What is it?
Gram staining is a differential bacterial staining method used to distinguish between Gram Positive and Gram Negative types of bacteria based on the makeup of their cell walls.

It is both the most used and significant staining method in bacteriology, particularly in medical bacteriology. It is frequently the initial test carried out on bacteria during the process of their identification and observation.

Two stains are used in this staining method
Safranine as a counterstain and crystal violet as the primary stain. Gram-positive bacteria will retain their primary stain and appear violet or purple. Gram-Positive bacteria are what these organisms are known as.

Under a microscope, the Gram-Negative bacteria in the other group will lose their primary stain and take up the counterstain, making them appear pink or red. Gram-Negative bacteria are what these organisms are known as. The differential staining technique is named as such because it allows bacteria to be divided into two categories.

History of Gram Staining
Hans Christian Gram, a Danish bacteriologist, developed this method in 1884. (1853 September 13 to 1938 November 14). He created this staining method to find the pneumonia-causing bacteria. The division of bacteria into Gram Positive and Gram Negative kinds later gained popularity. 

Gram Staining Theory
Based on the variations in the composition and structure of bacterial cell walls, gram staining and differentiation are performed. Bacteria with extensive peptidoglycan layers on their cell walls will resist the primary stain’s ability to fade, remaining violet or purple in hue. Bacteria with a thin peptidoglycan coating and little cross-linkage gain a pink or red counterstain in place of the primary stain following decolorization.