Question

Why wouldn't the Gram stain procedure be useful in distinguishing between the cells in a Pseudomonas aeruginosa culture from the cells in a Klebsiella pneumoniae culture?

Answer 1

Ans: Gram staining can't be useful for distinguishing Psudomonas aeruginosa cells from Klebsiella pneumoniae because this staininig procedure is totally dependent on the cell wall composition of the grame +ve and gram -ve cell. The gram positive cell wall is thick having several layer of peptidoglycan and gram negative cell wall is thin having mainly Lipopolysaccharides in the cell wall. Because of this compostion difference Gram staining is used to distinguish between gram +ve cells and gram -ve cells.

But in this both Pseudomonas aeruginosa and Klebsiella pneumoniae are gram negative strain, which means both have same cell wall composition and that is why they do not sitinguished by gram staining.