Question

If a student used Safranin as the primary stain and crystal violet as the secondary during the gram stain procedure, how would it affect the results?

Be sure to include what colors the gram positive and gram negative will be and whether the mistake will give you a false positive or a false negative result.

Answer 1

The safaranin used as primary stain is taken up by both gram positive and gram negative bacteria after using decolorizing agent gram negative will wash off the safranin color while gram postive having thick layer of peptidoglycan doesnot allow free flow of color by alcohol , thus on adding secondary stain the gram negative bacteria will have voilet color and gram positive bacteria will have safranin color as it retain primary stain. So it give false postive color in both the bacteria .