Question

How do I differentiate gram positive and gram negative Bacteria?

Answer 1

Gram-Positive Bacteria: -

1. The bacteria which retain the purple stain in gram-staining technique, are called gram-positive bacteria.
2. Gram-positive bacteria are non-motile, spore producing, and less resistant to antibiotics.
3. Examples: Staphylococcus aureus, Diploococcus pneumoniae.

Gram-Negative Bacteria: -

1. Gram-negative bacteria are bacteria that do not retain the crystal violet stain employed in the gram-staining method of bacterial differentiation.
2. Gram-negative bacteria are generally motile, non-spore producing, and more resistant to antibiotics.
3. Examples: E.coli, Vibriocholerae.

Gram-Positive Bacteria	Gram Negative Bacteria
After gram staining, it takes on a distinct purple hue.	After gram staining, the colour is pale reddish.
2. Higher amount of peptidoglycan is present in the cell wall.	2. Less amount of peptidoglycan is present in the cell wall.
3. Generally, flagella are not found.	3. Usually, flagella are found.
4. There is no lipid membrane on the outside.	4. There is an outer lipid membrane.
5. Examples: Staphylococcus aureus, Diploococcus pneumoniae.	5. Examples: E.coli, Vibriocholerae.