Question

Are Gram-negative bacteria harmful?

Answer 1

Gram-negative bacteria:

1. Gram-negative bacteria possess a thin peptidoglycan layer surrounded by an outer lipid membrane.
2. They do not retain the crystal violet stain (Gram stain) during the staining process; hence called Gram-negative.
3. Gram-negative bacteria are harmful. They cause several diseases.

Examples of harmful Gram-negative bacteria:

1. Pseudomonas aeruginosa causes pneumonia and septicemia.
2. Helicobacter pylori causes peptic ulcers and gastritis.