Mycoplasma, mycoplasma, is the smallest known free-living organism and the smallest prokaryotic cell. It is a prokaryotic microorganism larger than a virus and smaller than a bacterium, and their distinguishing feature is the absence of a cell wall. As a result, the cells are soft, morphologically variable and highly polymorphic. Mycoplasma cells are observed under electron microscopy and are seen to have a cell membrane with ribosomes, RNA and circular DNA inside the cells.Mycoplasma is widely found in soil, sewage, insects, vertebrates and humans, and is one of the pathogenic bacteria of plants, animals and humans. Mycoplasma is another category of microscopic pathogens different from bacteria and fungi. There are more than 80 species of mycoplasma genera, and the mycoplasmas associated with humans are Mycoplasma pneumoniae, Mycoplasma humanum, Mycoplasma solium and Mycoplasma genitalium, the former causing pneumonia and the latter three causing genitourinary tract infections. Mycoplasma genitalium infections in the genitourinary tract cause diseases such as non-gonococcal urethritis in men and mainly non-gonococcal genitourinary tract infection in women. Men present with urethral tingling, burning sensation and difficulty in urination, and in a few cases, frequent urination. The urethral opening is mildly red and swollen, and the discharge is thin, and some patients are asymptomatic. In women, the symptoms are increased leucorrhea, burning in the urethra or infertility, miscarriage and ectopic pregnancy caused by pelvic inflammatory disease and tubal inflammation. Chlamydia is a very widely spread pathogen in nature. They are mostly spherical and pile-shaped, have cell walls and are generally parasitic in animal cells. Once upon a time they were classified as viruses, but later they were found to be a class of their own. It is a prokaryotic microorganism larger than viruses and smaller than bacteria, spherical in shape, only O.3-0.5 microns in diameter, it is not motile, chlamydia is widely parasitic in humans, mammals and birds, only a few have pathogenicity. Chlamydia is a Gram-negative pathogen, a specialized intracellular microorganism that has no ability to synthesize the high-energy compounds ATP and GTP, which must be provided by the host cell, thus becoming an energy parasite. Chlamydia is a class of prokaryotic cellular microorganisms that can pass through cellular filters, have a unique developmental cycle, and are strictly intracellular parasites. It is mainly transmitted through sexual contact, and when it enters the reproductive tract, it likes to enter the mucosal cells to grow and multiply, causing endometritis, tubitis, pelvic inflammatory disease, and urethritis in women. In men, it can cause urethritis, epididymitis, proctitis and other inflammatory diseases. In women, Chlamydia trachomatis infection can cause infertility, ectopic pregnancy (ectopic pregnancy), miscarriage, stillbirth, premature rupture of fetal membranes, and preterm birth. When Mycoplasma and Chlamydia infect the body, they first invade the columnar epithelial cells and grow and multiply inside the cells, and then enter the cells of the mononuclear macrophage system to proliferate. As mycoplasma and chlamydia multiply within the cells, they cause the death of the infected cells, while still evading the host’s immune defenses and receiving intermittent protection. The pathogenic mechanism of mycoplasma and chlamydia is the inhibition of infected cell metabolism, lysis and destruction of cells and leads to the release of lysozyme, cytotoxic effects of metabolites, causing metamorphic reactions and autoimmunity. When the body is infected with mycoplasma and chlamydia, specific immunity is produced, but this immunity is weak and short-lived; therefore, mycoplasma and chlamydia infections tend to cause persistent, recurrent infections, and occult infections. In terms of cellular immunity, most patients with active cured chlamydia often cause a delayed metaplasia when the corresponding antigen is given intradermally. This metaplasia can be passively transferred by lymphocytes. This immunity is most likely mediated by T cells. In terms of humoral immunity, neutralizing antibodies appear in the serum and local secretions after mycoplasma and chlamydia infections. Neutralizing antibodies prevent the adsorption of chlamydia to host cells and also enhance phagocytic uptake through conditioning. The most common site of invasion of mycoplasma and chlamydia in the female reproductive tract is the cervix, and the resulting upward spread can cause endometritis, tubitis, pelvic inflammatory disease, and also acute urethritis and vestibular adenitis. Mycoplasma and chlamydia infections in pregnant women can cause neonatal ophthalmia and pneumonia if the fetus passes through the birth canal during delivery. Mycoplasma and chlamydia infections in women do not always cause symptoms, and even if they do, they vary depending on the site of infection. For example, cervical infections can cause cervical erosion, cervical mucosal edema, increased leucorrhea (purulent), and contact bleeding, while tubal infections can cause lower abdominal pain, lumbago, and infertility. In general, none of these symptoms are specific. Mycoplasma and Chlamydia can be transmitted through sexual contact, but also through hands, eyes, towels, clothing, baths, stools and swimming pools. Sexual relations with more than one person, the male partner has a UTI, poor hygiene habits, etc. are prone to infection. Therefore, the key to preventing infection is to be clean and take good care of your personal hygiene. Mycoplasma pneumonia is also transmitted through the respiratory tract. It is important to pay attention to isolation. Several other types of mycoplasma infections are mainly transmitted through sexual contact, so families should not share bathing utensils, and underwear should be washed and disinfected separately. So, children’s and adults’ clothes (especially underwear) should be washed separately.