Differences between Gram Positive and Gram Negative Bacteria 4.43/5 (729)

Differences between Gram Positive and Gram Negative Bacteria

Differences between Gram Positive and Gram Negative Bacteria



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

Differences between Gram Positive and Gram Negative Bacteria

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Sagar Aryal

I am Sagar Aryal, a passionate Microbiologist and the Scientific Blogger. I did my Master's Degree in Medical Microbiology and currently working as a Lecturer at Department of Microbiology, St. Xavier's College, Kathmandu, Nepal. I am particularly interested in research related to Medical Microbiology and Virology. Find me on Facebook, Twitter or Linkedin !!!


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  1. Please I like to send me microbiology not

  2. Please I like to send me microbiology not

  3. 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

  4. 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.

  5. which Bacteria do sporulate ? gram + or gram – ? thank you

    1. Gram positive

  6. thanq for valuable information

  7. Thanks all for your imput

  8. I am new student of microbiology thank you for information

  9. Thanks….very useful info…

  10. 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.

  11. Thanks for sharing knowledge and provide us the platform to gain it

  12. very useful information !! Thanks to you sir. it is one of the good informative page for biotechnology and microbiology students.

  13. fantastic work! every piece of infprmation i needed is here.

  14. 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?

  15. Good site,what is the relationship between endospores stain and gram nagetive and gram positive stain…?

  16. I got done with my homework mutch faster. Thank you so much

  17. 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)

  18. 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.

  19. Please just explain the diffrnces b/w gram positve nd negative bactria clearly

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

  20. 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

  21. Dear Sagar, very good job, could you publish some topics regarding Food&Dairy microbiology.

  22. What are the general characteristics of both fungi and protozoa?

    1. 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

  23. Please also add types of diseases caused by them.

  24. 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

  25. I want the notes on ED pathway….admin, can you provide please.

    1. Oks very soon. thanks

  26. This site page not fully show so plz size increase this page

    1. ACWannabeBiotechQueen

      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.

  27. 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?

  28. Gratulation I again read all You make this articul best last also was Prima!
    Best regards

  29. very useful information !!

  30. bradfordmukungwana

    I need nots on biochemistry

  31. good work,kindly sir,can u send me the micro text book? i, am 3rd year mbbs student ,needs the micro text

  32. 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

  33. José A. Álvarez

    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.

    1. royal arpanz bantawa

      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..

    2. ACWannabeBiotechQueen

      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.

  34. realy apreciable…I need ur help…

  35. can u plz send me ur post by mail

  36. Mumtaz Ali Sanjrani

    It is one of the informative activity for Microbiology students

  37. Thanks for sending books

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