Mycoplasma genitalium

Mycoplasma genitalium (MG, commonly known as Mgen), is a sexually transmitted, small and pathogenic bacterium that lives on the skin cells of the urinary and genital tracts in humans. Mgen is becoming increasingly common. Resistance to multiple antibiotics is occurring, including azithromycin which until recently was the most reliable line treatment. The bacteria was first isolated from 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 homosexual men and those previously treated with the azithromycin antibiotics. Specifically, it causes urethritis in both men and women, and also 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. Its complete genome sequence was published in 1995 (size 0.58 Mbp, with 475 genes). It was regarded as a cellular unit with the smallest genome size (in Mbp) until 2003 when a new species of Archaea, namely Nanoarchaeum equitans, was sequenced (0.49 Mbp, with 540 genes). However, Mgen still has the smallest genome of any known (naturally occurring) self-replicating organism and thus is often the organism of choice in minimal genome research. The synthetic genome of Mgen named Mycoplasma genitalium JCVI-1.0 (after the research centre, J. Craig Venter Institute, where it was synthesised) was produced in 2008, becoming the first organism with a synthetic genome. In 2014, a protein was described called Protein M from M. genitalium. Infection with Mgen produces a combination of clinical symptoms, but can be asymptomatic. It causes inflammation in the urethra (urethritis) both in men and women, which is associated with mucopurulent discharge in the urinary tract, and burning while urinating. In women, it causes cervicitis and pelvic inflammatory diseases (PID), including endometritis and salpingitis. Women may also experience bleeding after sex and it is also linked with tubal factor infertility. For men, the most common signs are painful urination or a watery discharge from the penis. 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 Mycoplasma, the infection is not associated with bacterial vaginosis. It is highly associated with the intensity of HIV infection. Some scientists are doing research to see 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 consists of 525 genes 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 random sequencing in 1993, by which they found 100,993 nucleotides and 390 protein-coding genes. Collaborating with researchers at the Institute for Genomic Research, which included Craig Venter, they made the complete genome sequence in 1995 using shotgun sequencing. Only 470 predicted coding regions (out of 482 protein encoding genes) were identified, including genes required for DNA replication, transcription and translation, DNA repair, cellular transport, and energy metabolism. It was the second complete bacterial genome ever sequenced, after Haemophilus influenzae. 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 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. 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. M. genitalium is strongly associated with HIV-1. Recent research shows that prevalence of Mgen is currently higher than other commonly occurring STIs (Sexually Transmitted Infections). Mgen is a fastidious organism with prolonged growth durations. This makes detection of the pathogen in clinical specimens and subsequent isolation, extremely difficult. Lacking a cell wall, mycoplasma remains unaffected by commonly used antibiotics. The absence of specific serological assays leaves nucleic acid amplification tests (NAAT) as the only viable option for detection of Mgen DNA or RNA. However, samples with positive NAAT for the pathogen should be tested for macrolide resistance mutations, which are strongly correlated to azithromycin treatment failures, owing to rapid rates of mutation of the pathogen. Mutations in the 23S rRNA gene of Mgen have been linked with clinical treatment failure and high level in vitro macrolide resistance. Macrolide resistance mediating mutations have been observed in 20-50% of cases in the UK, Denmark, Sweden, Australia, and Japan. Resistance is also developing towards the second-line antimicrobials like fluoroquinolone. According to the European guidelines, the indication for commencement of diagnosis for Mgen infection are: