Mycoplasma Hominis: Infection, Transmission & Diseases

Mycoplasma hominis is the name given to a species of bacteria that inhabits the intestine of humans as a commensal. The germ can sometimes cause urinary tract infections.

What is Mycoplasma hominis?

Mycoplasma hominis is a member of the Mycoplasmataceae family. Mycoplasmas or mycoplasmas are among the cell wall-less bacteria and are related to ureaplasmas. The only reservoir for Mycoplasma hominis is humans. The bacterial species is found, among other places, in the intestinal flora of humans. Since there is a proximity to the urogenital area, the pathogen triggers urinary tract diseases in some people. Mycoplasmas belong to the class of mollicutes (soft-skinned organisms) and have a very small genome. For this reason, they are also interesting for genetics. If disease occurs due to Mycoplasma hominis or other mycoplasmas, the medical term is mycoplasma infection.

Occurrence, distribution, and characteristics

Mycoplasmas are among the smallest bacterial species. For example, Mycoplasma hominis reaches a size of only 0.1 to 0.6 µm. The bacterium is endowed with both DNA and RNA. However, although mycoplasmas are considered to be exceedingly flexible, they exhibit little osmotic resistance. Therefore, Mycoplasma hominis cannot be labeled by Gram staining. For this reason, the administration of beta-lactam antibiotics does not achieve success in Mycoplasma hominis infection. Thus, these only achieve an effect in those bacteria from which a cell wall is built up that has a murein layer. The enzyme lysozyme, which occurs in the endosome, is equally ineffective. One of the typical characteristics of Mycoplasma hominis is that the bacterium is unable to synthesize cholesterol, which is due to its altered metabolism. For this reason, a host cell is required by the bacterial species in order to grow. Furthermore, Mycoplasma hominis is equipped with special surface molecules. However, these are not pili. Nevertheless, as cytoadhesins, they enable attachment to the epithelium of the intestine. Mycoplasma hominis is widespread throughout the world. It is estimated that Mollicutes have existed for 65 million years and have very efficient survival mechanisms. Since they reach only a tiny size, have no cell wall and are very simply equipped and deformable, they are considered perfectly equipped for a parasitic existence. In doing so, they are able to attach themselves tightly to the membranes of their host cells. However, if necessary, they can also perform gliding movements and achieve mobility. As a commensal, Mycoplasma hominis lives in the intestine and urogenital tract of humans. Unlike a regular parasite, a commensal feeds on the food residues of the host body. However, the bacterium does not usually cause damage to the organism, although it does use the human body to its advantage. If the person’s immune system functions smoothly, Mycoplasma hominis cannot exert a pathogenic effect and is classified as apathogenic. Some mycoplasma is also found on the genital mucosa.

Diseases and symptoms

Under certain circumstances, Mycoplasma hominis can exert a pathogenic effect. This applies primarily to people who suffer from a local or general weakening of their immune system. This results, for example, from treatment with antibiotic drugs. The same applies to surgical procedures, the birth process or cancer. Local inflammations are sometimes triggered by Mycoplasma hominis. These include, in particular, urethritis (inflammation of the urethra), inflammation of the renal pelvis, the uterus or vagina, and the male prostate gland (prostate). In addition, advancing infections are possible, with affected individuals suffering from general symptoms or fever. Furthermore, mycoplasma can be transmitted through sexual intercourse. For this reason, mycoplasma infections are categorized as sexually transmitted diseases. However, it is controversial whether the bacteria are also responsible for infertility and miscarriages. The number of mycoplasmas on the genital mucosa depends on how sexually active a person is and how many sexual partners they have. Thus, greater amounts of mycoplasma are found in people who frequently engage in sexual intercourse with changing partners.In principle, antibodies against mycoplasma can be detected in the blood of about 95 percent of all middle-aged people. The symptoms caused by Mycoplasma hominis are often non-specific and only mild. Moreover, they depend on the body site where the inflammation occurs. Most patients suffer from a burning sensation during urination, pain in the area of the kidneys or yellowish discharge. Clarifying the cause of an infection with Mycoplasma hominis is not always easy, since the bacterium is also present in healthy people. It is possible to cultivate the germ on a special nutrient medium. Urine, swabs from the vagina or urethra of women, and prostatic secretions or ejaculate from men can be used as examination material. Treatment of an infection with Mycoplasma hominis is carried out with antibiotics. However, not all agents of this type are suitable for therapy, since mycoplasmas do not have a cell wall. For example, the pathogens are resistant to penicillin. Instead, antibiotics such as erythromycin, which have other mechanisms of action, are used.