Answer: yes. In his article "The End of Antibiotics and the Rise of Iodine as an Effective Alternative" Mark Sircus, OMD, says "Though it kills 90 percent of bacteria on the skin within 90 seconds, its use as an antibiotic has been ignored. Iodine exhibits activity against bacteria, molds, yeasts, protozoa, and many viruses; indeed, of all antiseptic preparations suitable for direct use on humans and animals and upon tissues, only iodine is capable of killing all classes of pathogens: gram-positive and gram-negative bacteria, mycobacteria, fungi, yeasts, viruses and protozoa. Most bacteria are killed within 15 to 30 seconds of contact." See the full article at
If iodine is not applied, both the gram-positive and gram-negative stains will appear to be gram-negative. The iodine acts as a mordant that helps to fix the crystal violet stain in the gram-positive bacteria, making them appear purple. Without iodine, the crystal violet stain can be easily washed out of both gram-positive and gram-negative bacteria, resulting in a pink or red color.
Gram positive cells take up the crystal violet, which is then fixed in the cell with the iodine mordant. This forms a crystal-violet iodine complex which remains in the cell even after decolorizing. It is thought that this happens because the cell walls of gram positive organisms include a thick layer of protein-sugar complexes called peptidoglycans. This layer makes up 60-90% of the gram positive cell wall. Decolorizing the cell causes this thick cell wall to dehydrate and shrink, which closes the pores in the cell wall and prevents the stain from exiting the cell. At the end of the gram staining procedure, gram positive cells will be stained a purplish-blue color. Gram negative cells also take up crystal violet, and the iodine forms a crystal violet-iodine complex in the cells as it did in the gram positive cells. However, the cell walls of gram negative organisms do not retain this complex when decolorized. Peptidoglycans are present in the cell walls of gram negative organisms, but they only comprise 10-20% of the cell wall. Gram negative cells also have an outer layer which gram positive organisms do not have; this layer is made up of lipids, polysaccharides, and proteins. Exposing gram negative cells to the decolorizer dissolves the lipids in the cell walls, which allows the crystal violet-iodine complex to leach out of the cells. This allows the cells to subsequently be stained with safranin. At the end of the gram staining procedure, gram negative cells will be stained a reddish-pink color. Remember:
Over destaining can cause the purple color from the gram positive bacteria to be washed away, so when you apply the safrinin the gram positive bacteria will take up a pink color causing gram positive bacteria to appear gram negative.
Iodine is used as a mordant in the gram staining procedure to make large crystals when it is used with crystal violet dye. In gram positive cell walls those crystals get stuck and wont get washed off with the alcohol. In gram negative cell walls the crystals are washed out.
Iodine is used in Gram staining to form a complex with crystal violet, which helps to trap the dye within the cell wall of Gram-positive bacteria. This step is important in differentiating between Gram-positive and Gram-negative bacteria based on their ability to retain the crystal violet dye.
Amoebas are not bacteria and therefore do not have a gram classification. They are eukaryotic organisms belonging to the phylum Rhizopoda.
No, iodine is not a basic stain. Iodine is commonly used in Gram staining to identify bacteria as either Gram-positive or Gram-negative based on their cell wall composition. It acts as a mordant in the staining process and helps to fix the crystal violet stain in Gram staining.
____________Color of Gram-positive_______Color of Gram-negativePrimary stainCrystal violet_____Purple____________________ PurpleMordant:Iodine____________Purple________________________PurpleDecolorizing agent:Alcohol-acetone__ Purple____________________ ColorlessCounterstain:Safranin___________Purple_________________________Red
gram negative
gram positive
Plasmodium is not a bacteria to be classified whether gram negative or gram positive. It is a genus of parasitic protists. Infection by these organisms is known as malaria.
its gram negative