Pathogenic bacteria mainly include non-cellular microorganisms, prokaryotic cellular microorganisms, eukaryotic cellular microorganisms, such as viruses, bacteria, fungi and so on. 1. Non-cellular microorganisms: mainly include viruses and prions, viruses have no cellular structure. After infection, human body may have many diseases such as hepatitis A and new coronavirus pneumonia. Prions are infectious protein molecules, which can cause mad cow disease in animals and Kuru disease in humans. 2. Prokaryotic microorganisms: mainly bacteria, rickettsiae, chlamydia, mycoplasma, spirochetes, etc. These microorganisms have no cellular organelles. After the human body is infected with prokaryotic microorganisms, acute tonsillitis, tuberculosis and other diseases, as well as cystitis, urethritis and other diseases. 3. Eukaryotic microorganisms: mainly including fungi, protozoa, etc., human infection with eukaryotic microorganisms will appear trichomoniasis, tinea pedis, vulvovaginal pseudomycosis and other diseases. The causative organisms include many kinds of bacteria, which can lead to diseases of organs or tissues in the human body. Patients should seek medical attention when symptoms of pathogenic bacterial infections occur. Note: The terms “new coronavirus pneumonia” and “new coronavirus pneumonia” mentioned in this article were renamed to “new coronavirus infection” on December 26, 2022, as announced by the National Health Commission.