Question: what are the biggest bacteria that causes desiese

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  1. The largest bacterial species I know of is called Thiomargarita namibiensis and is found in the coastal waters of Namibia. The largest one ever found was 0.75mm wide which is big enough to be seen without a microscope! Most bacterial species are approximately 1 micrometer wide which is 750 times smaller than T. namibiensis. As far as I know though it does not cause disease in humans.

    Most disease causing bacteria are approximately 1 micrometer across, any bigger and they would have trouble actually causing disease.

    Instead of the largest pathogen (fancy word for disease causing bacteria) I can tell you the pathogen with the biggest genome ( is Pseudomonas aeruginosa which has 6.3 billion base-pairs which is about the same as you have in each of your cells, except all of your cells have to work together to make you, you!



  1. Wrong end of the size scale for me 🙂


  2. Wow, T. namibiensis is wide enough to see with your eyes! I just learnt something really cool. Thanks James, and thanks addzyy69 for your fantastic question. 🙂