Mycoplasma genitalium бактериясы және оның медициналық аспектілері

Species of bacterium

Speciesbox
| image = 3D Whole Cell (3D WC) model of a Mycoplasma genitalium cell. jpg
| image alt =
| image caption = 3D Whole Cell (3D WC) model of a Mycoplasma genitalium cell
| genus = Mycoplasmoides
| species = genitalium
| authority = (Tully et al. 1983) Gupta et al. 2018, Mgen, or since 2018, Mycoplasmoides genitalium) is a sexually transmitted, small and pathogenic bacterium that lives on the mucous epithelial cells of the urinary and genital tracts in humans. Medical reports published in 2007 and 2015 state that Mgen is becoming increasingly common. Resistance to multiple antibiotics, including the macrolide azithromycin, which until recently was the most reliable treatment, is becoming prevalent. The bacteria was first isolated from the urogenital tract of humans in 1981, and was eventually identified as a new species of Mycoplasma in 1983. It can cause negative health effects in men and women. It also increases the risk factor for HIV spread with higher occurrences in those previously treated with the azithromycin antibiotics.

Mgen is a bacterium recognized for causing urethritis in both men and women along with cervicitis and pelvic inflammation in women. It presents clinically similar symptoms to that of Chlamydia trachomatis infection and has shown higher incidence rates, compared to both Chlamydia trachomatis and Neisseria gonorrhoeae infections in some populations. Infection with Mgen can be symptomatic or asymptomatic. Both men and women may experience inflammation in the urethra (urethritis), characterized by mucopurulent discharge in the urinary tract, and burning while urinating. In women, it causes cervicitis and pelvic inflammatory diseases (PID), including endometritis and salpingitis. For men, the most common signs are painful urination or a watery discharge from the penis. There is a consistent association of M. genitalium infection and female reproductive tract syndromes. M. genitalium infection was significantly associated with increased risk of preterm birth, spontaneous abortion, cervicitis, and pelvic inflammatory disease. In addition, this pathogen may latently infect the chorionic villi tissues of pregnant women, thereby impacting pregnancy outcome. Infertility risk is also strongly associated with infection with M. genitalium, although evidence suggests it is not associated with male infertility. When M. genitalium is a co infectious agent risk associations are stronger and statistically significant. Polymerase chain reaction analyses indicated that it is a cause of acute non gonococcal urethritis (NGU) and probably chronic NGU. It is strongly associated with persistent and recurring non gonococcal urethritis (NGU) responsible for 15 percent to 20 percent of symptomatic NGU cases in men. Unlike other mycoplasmas, the infection is not associated with bacterial vaginosis. It is highly associated with the intensity of HIV infection. Some scientists are performing research to determine if Mgen could play a role in the development of prostate and ovarian cancers and lymphomas in some individuals. These studies have yet to find conclusive evidence to suggest a link.

The genome of M. genitalium strain G37T consists in one circular DNA of 580,070 base pairs. Scott N. Peterson and his team at the University of North Carolina at Chapel Hill reported the first genetic map using pulsed field gel electrophoresis in 1991. They performed an initial study of the genome using sequencing in 1993, by which they found 100,993 nucleotides and 390 protein coding genes. Collaborating with researchers at The Institute for Genomic Research (TIGR; now the J. Craig Venter Institute), which included Craig Venter, they made the complete genome sequence in 1995 using shotgun sequencing. It is unclear where the "525" gene count for the G37T stems from and what gene calling procedure was used. In 2006, the team at the J. Craig Venter Institute reported that only 382 genes are essential for biological functions. The small genome of M. genitalium made it the organism of choice in The Minimal Genome Project, a study to find the smallest set of genetic material necessary to sustain life. There is limited divergence among clinical strains of M. genitalium. All strains retain the small genome size.

Owing to the widespread macrolide resistance, samples that are positive for Mgen should ideally be followed up with an assay capable of detecting mutations that mediate antimicrobial resistance. The European Guideline on Mgen infections, in 2016, recommended complementing the molecular detection of Mgen with an assay capable of detecting macrolide resistance associated mutations.

The discovery of Protein M, a new protein from M. genitalium, was announced in February 2014. The protein was identified during investigations on the origin of multiple myeloma, a B cell hematologic neoplasm. To understand the long term Mycoplasma infection, it was found that antibodies from multiple myeloma patients' blood were recognised by M. genitalium. The antibody reactivity was due to a protein never known before, and is chemically responsive to all types of human and nonhuman antibodies available. The protein is about 50 kDa in size, and composed of 556 amino acids. Mgen evolved from a gram positive ancestor that was clostridium like but has lost the genes to code for the enzymes involved in de novo nucleic acid synthesis, amino acid synthesis, and synthesis of fatty acids. This means that Mgen needs the host's growth factors to keep reproducing. Although Mgen has abilities that help it adhere to cells, it is still unknown how the bacteria can maintain an infection inside the epithelial cells of the ectocervix and vagina when shedding of the apical layer of cells occur. The organism's ability to have adhesion to host cells relies of two proteins, P110 and P140. Adhesion is an important step in beginning an infection in a cell and Mgen can adhere to spermatozoa, erythrocytes, and epithelial cells. The terminal organelle relies on these proteins as well because without them the organelle was not present. The segmented pair plates of Mgen is a core of dense electrons which is anchored to the cell membrane. The end of this core is in contact with the wheel complex and the wheel complex contains the proteins MG219, MG200, MG386, and MG491 which aid in the gliding motility of the bacteria. Although Mgen lacks secreted virulence factors, the protein MG186 degrades host nucleic acids due to it being a calcium dependent membrane associated nuclease.