Gram's staining method was developed by which scientist?

Gram's staining method was developed by which scientist?

• A. Louis Pasteur
• B. Hans Christian Gram
• C. Robert Koch
• D. Alexander Fleming

Answer: (B)

Gram staining is a differential staining technique used to classify bacteria by their cell wall properties. It was developed by Hans Christian Gram, a Danish bacteriologist, in the 1880s. The method uses a sequence of dyes so that Gram-positive bacteria retain the purple crystal violet stain, while Gram-negative bacteria do not and take up the counterstain, appearing pink or red. This distinction helps identify bacteria and guides treatment choices because Gram-positive and Gram-negative organisms often differ in their response to antibiotics. Other scientists listed made major contributions in microbiology, but they did not create Gram’s staining method: Pasteur advanced germ theory and vaccines, Koch formulated postulates and linked microbes to diseases, and Fleming discovered penicillin.

Gram staining is a differential staining technique used to classify bacteria by their cell wall properties. It was developed by Hans Christian Gram, a Danish bacteriologist, in the 1880s. The method uses a sequence of dyes so that Gram-positive bacteria retain the purple crystal violet stain, while Gram-negative bacteria do not and take up the counterstain, appearing pink or red. This distinction helps identify bacteria and guides treatment choices because Gram-positive and Gram-negative organisms often differ in their response to antibiotics. Other scientists listed made major contributions in microbiology, but they did not create Gram’s staining method: Pasteur advanced germ theory and vaccines, Koch formulated postulates and linked microbes to diseases, and Fleming discovered penicillin.