Principles of Bacteria

Bacteria are unicellular microorganisms which are composed of a naked DNA chromosome, cytoplasm, cell membrane and cell wall.

– They can be divided into Gram Positive and Negative bacteria

i) Gram Positive – cell wall made of peptidoglycan, take up Gram stain

ii)Gram Negative – has a cell wall of peptidoglycan but then an additional outer membrane too, do not take up Gram Stain

Bacteria can be classified by Gram Stain, shape, enzymes and whether they are aerobic or anaerobic. This will all affect diagnosis and treatment options.

– The diagram below summarises the main bacteria in each category (not exhaustive list):

Slides and Images

1. Microrao / CC BY-SA (https://creativecommons.org/licenses/by-sa/4.0)
2. Dr. Sahay / CC BY-SA (https://creativecommons.org/licenses/by-sa/4.0)
3. HansN. / CC BY-SA (https://creativecommons.org/licenses/by-sa/3.0)
4. Dr. Sahay / CC BY-SA (https://creativecommons.org/licenses/by-sa/3.0)
5. Dr. Richard Facklam, USCDCP / public domain (CC0)
6. CDC – Public Health Image Library / Public Domain
7. CDC/Dr. Stuart E. Starr / Public domain
8. CDC/Don Stalons / Public domain
9. CDC – Public Health Image Library / Public Domain
10. CDC – Public Health Image Library / Public Domain
11. Xishan01 – BY CC (https://creativecommons.org/licenses/by-sa/3.0/)
12. CDC/ Dr. Norman Jacobs / Public domain
13. BiotechMichael / Public domain
14. CDC / Public domain
15. Madprime / CC0
16. USCDCP / Public Domain
17. Eukaryotica / Public Domain
18. CDC – Public Health Image Library / Public Domain

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