Gram's stain

noun \ˈgramz-\

Definition of GRAM'S STAIN

: a method for the differential staining of bacteria by treatment with a watery solution of iodine and the iodide of potassium after staining with a triphenylmethane dye (as crystal violet) —called also Gram's method

: the chemicals used in Gram's stain

Variants of GRAM'S STAIN

Gram's stain or Gram stain \ˈgram-\

Origin of GRAM'S STAIN

Hans C. J. Gram †1938 Danish physician

First Known Use: 1903

Medical Dictionary

Gram's stain

noun

Medical Definition of GRAM'S STAIN

: a method for the differential staining of bacteria that involves fixing the bacterial cells to a slide and staining usually with the basic dye crystal violet, treating with an iodine solution to fix the dye, washing with acetone or alcohol to decolorize the dye, and counterstaining usually with a red safranine dye which shows up only if the crystal violet has been decolorized, that results in gram-positive bacteria retaining the purple dye and gram-negative organisms having it decolorized so that the red counterstain shows up, and that is believed to depend on differences in the structure and composition of the bacterial cell walls which facilitate or prevent the decolorization of the crystal violet dye by the alcohol or acetone—called also Gram's method

: the chemicals used in Gram's stain