Expert: Walter Hintz - 10/6/2005

Question
Hi, my question is ..........  Can iodine be added before the primary stain in a Gram stain?

and also Which step can be omitted without affecting determination of teh Gram stain?  Crystal violet, Gram's iodine, Alcohol, or Safranin?

Thanks!!!!

Answer
Hi Kristi
 No The iodine sets the violet stain on Gram positives.
 You could omit the safranin counter stain because if the gern is gram positive the alcohol will not decolorize and if it does you know it is gram negative.  The counter stain is needed to see the gram negatives.