Differences between Gram Positive and Gram Negative Bacteria

S.N. Characteristics Gram Positive Gram Negative
1 Gram Reaction Gram Positive Stain

Retain crystal violet dye and stain blue or purple

Gram Negative Stain

Can be decolorized to accept counterstain (safranin) and stain pink or red

2 Cell Wall Cell Wall is 20-30 nm thick. Cell Wall is 8-12 nm thick.
3 Cell Wall The wall is Smooth. The wall is wavy.
4 Peptidoglycan Layer Thick (multilayered) Thin (single-layered)
5 Teichoic Acids Present in many Absent
6 Periplasmic Space Absent Present
7 Outer Membrane Absent Present
8 Porins Absent Occurs in Outer Membrane
9 Lipopolysaccharide (LPS) Content Virtually None High
10 Lipid and Lipoprotein Content Low (acid-fast bacteria have lipids linked to peptidoglycan) High (because of presence of outer membrane)
11 Mesosomes Quite Prominent Less Prominent
12 Flagellar Structure 2 rings in basal body 4 rings in basal body
13 Toxin Produced Exotoxins Endotoxins or Exotoxins
14 Resistance to Physical Disruption High Low
15 Cell Wall Disruption by Lysozyme High Low (requires pretreatment to destabilize outer membrane)
16 Susceptibility to Penicillin and Sulfonamide High Low
17 Susceptibility to Streptomycin, Chloramphenicol and Tetracycline Low High
18 Inhibition by Basic Dyes High Low
19 Susceptibility to Anionic Detergents High Low
20 Resistance to Sodium Azide High Low
21 Resistance to Drying High Low

24 thoughts on “Differences between Gram Positive and Gram Negative Bacteria

  1. Thanks alot I’m a clinical medicine and surgery student under microbiology unit I had to study about gram positive and negative so you’ve made it easier for me God bless

  2. I Would like to know the fundamental characters that differentiates these two.All you have mentioned are the secondary one,i guess.The distinction seems not clearly made on why one bacteria is called gram positive and the other negative.I would appreciate any notes regarding this.
    Hoping for your reply.

  3. In segment 13 i.e. Toxin production it is more accurate to write under gram negative bacteria exotoxins and/or endotoxins rather than exotoxins or endotoxins because endotoxins are produced by all gram negative bacteria as it ( the LPS) is an integral part of the outer membrane, so any species produce exotoxins will already produce both.

  4. If you are able to open the site in Chrome from your phone, you cannot see the entire page on the screen, but you can save the table to Drive in landscape as a PDF and it looks great.

  5. A good website…can i know the answers of these questions please?
    1:What are the basic requirements for a good germicide?
    2:Why is B.subtilis more resistant to phenol than e.coli?
    3:Do sensitive bacteria become resistant to antibiotics? if yes why?

  6. Thanks a lot
    if sources are in hand please send the characteristics of gram negative and positive bacteria on media’s (colony characterization, color etc)

  7. thank can i please know the source of this post? name of book, author and the page. thank you very much i used it for my homework and we are required to write the source.

    • gram positive have the ability to retain the color of the primary stain (crystal violet), while gram negative do not

  8. Anyone to give me the difference between the gram positive cell wall and gram negative cell wall,,, whenever i think i get less than three, please

    • Protozoan are mainly unicellular and microscopic. Fungi is majorly filamentous.
      Protozoan are parasitic , Fungi are parasitic and saprophytic

      amoebiasis, malaria , are some protozoan diseases

      major skin diseases aspergilloses, candidiasis, blstomycosis

  9. Please the topic is the diff between gram positive bacteria and gram negative bacteria but the distinction seem not to be clearly made. Pls help

  10. How does a a diderm or double cell walled bacteria like the Borrelia species fit in?
    Is there enough information to add a third column?

  11. Hlo sir im doing bsc biotech nd i want some guidance frm u fr msc studies .im interested in microbiology but im confused between biotech nd microbiology fr msc pls guide me nd sujust sm other gud fields olso fr masters thnku

  12. A very complete and useful tool for understanding. I consider that selected colors are confuse, because in a real Gram stain gramnegatives are pink and grampositives are violet, instead the colors showed in the figure.

    • yes you are very true…coz its very difficult todistinguished between this two gram bacteria on the basis of this grahm staning coz the colour seems same as pinkband violet..I think other innovative distinguishing colour should be prepared..

    • The colors of the illustration were poorly thought out, for sure, but I I always think
      POSITIVE (gram+) PURPLE (violet stain) PEPTIDOGLYCAN (thick)

      Because the G- stain varies from pink to red, I simply focus memorization by gram stain color for Positive Purple… in either/or items you only need to be obsessive about one OR the other…at least as one begins a journey into Microbial world.

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