Gram-Positive Bacteria

Gram-positive bacteria, which include staphylococci, streptococci, pneumococci, and bacteria that cause diphtheria and anthrax, are distinguished by their capacity to maintain the crystal violet stain in the Gram stain. When exposed to mordants like iodine and ethanol, these bacteria turn violet. Gram-positive bacteria’s cell wall is made up of multiple layers of peptidoglycan, resulting in a thick and strong structure. They also have teichoic acids and phosphates in their cell walls, which come in two forms: lipoteichoic acid and teichoic wall acid.

Gram-positive and gram-negative bacteria are two major groups of bacteria differentiated on the basis of their structure of the cell wall, and their response to a staining method called the gram stain. The main difference between Gram-positive and negative bacteria is the cell walls because of their structure and composition. Gram-positive bacteria have a thick peptidoglycan layer in their cell walls, which retains the crystal violet stain used during the staining process. While gram-negative bacteria have a thinner layer of peptidoglycan in their cell walls, which does not retain the crystal violet stain.

Gram Staining

Gram stain was developed by J.M.C. Gram, a bacteriologist from Denmark. This method uses a dye called crystal or gentian violet to differentiate between various types of bacteria. The ability of bacteria to retain the crystal violet stain determines their classification as either gram-positive or gram-negative. This staining technique is essential in identifying and characterizing different types of bacteria.