How does Pseudomonas aeruginosa appear after Gram staining?

What color does Pseudomonas aeruginosa turn after the primary stain is added?

Choose one: A. Pink B. Purple C. No color

Answer:

Pseudomonas aeruginosa appears pink after the primary stain is added.

Pseudomonas aeruginosa, a Gram-negative bacterium, does not retain the primary stain in Gram staining. After decolorization and the addition of a secondary stain (usually safranin), it appears pink.

The bacterium Pseudomonas aeruginosa is stained using the Gram stain method, which is a classic technique in Microbiology to identify bacteria. The color it turns after the primary stain (crystal violet) tells us about the structure of its cell wall. In the case of Pseudomonas aeruginosa, it is a Gram-negative bacterium, meaning that its cell wall is thin and does not retain the primary purple stain. After the application of the decolorizing agent and the secondary counterstain (usually safranin), Pseudomonas aeruginosa appears pink. So, After the primary stain is added and decolorization follows in the Gram stain process, Pseudomonas aeruginosa would be pink in color if a counterstain like safranin is used later.