Which may result in Gram-positive bacteria appearing to be Gram-negative?
A)Decolorizing too long
B)Decolorizing too short
C)Using old cultures
D)Using young cultures
E)Decolorizing too long AND using old cultures

Question

Quizplus · Accepted Answer

Decolorizing too long and using old cultures can both result in Gram-positive bacteria appearing to be Gram-negative. Decolorizing too long can remove the crystal violet from the Gram-positive bacteria, making them appear Gram-negative. Using old cultures can also result in Gram-positive bacteria appearing to be Gram-negative, as the cell walls of old bacteria are thinner and more easily decolorized.

Which May Result in Gram-Positive Bacteria Appearing to Be Gram-Negative