Treating gram negative bacteria with alcohol causes the dye

Treating gram negative bacteria with alcohol causes the dye to leave the bacteria whereas in gram positive bacteria it causes retention of the dye. Is this statement correct?

Solution

partially correct.

addition of crystal violet and iodine makes both Gram positive and Gram negative cells blue.

decolorization step differentiates between Gram positive and Gram negative bacteria.

decolorization solvent includes acetone or ethanol. Gram negative bacteria contain lipid rich thin cell walls, whereas, Gram positive bacteria consist of lipid poor thick cell walls.

Decolorization solvent such as ethanol extracts crystal violet- iodine complex from Gram negative bacteria to a greater extent than Gram positive bacteria.

therefore, the given statement: treating Gram negative bacteria with alcohol causes the dye to leave the bacteria- correct.

Whereas in Gram positive it causes retention of dye: Truly, it can not extract dye from Gram positive bacteria. It wont help in retention of dye. However, dye retains in Gram positive bacteria even after addition of alcohol.