genitalium

Mycoplasma genitalium is a small, cell-wall–deficient bacterium in the genus Mycoplasma and a human sexually transmitted pathogen. It has one of the smallest known self-replicating genomes, about 580 kilobases encoding roughly 500 genes. The absence of a cell wall makes it Gram-stain negative and complicates culture and antibiotic responses.

Transmission and disease: It is transmitted primarily through sexual contact. In men it can cause non-gonococcal urethritis; in women it can cause cervicitis and, less commonly, pelvic inflammatory disease. Many infections are asymptomatic, contributing to spread. Potential complications include infertility and adverse pregnancy outcomes in some settings.

Diagnosis and treatment: Diagnosis uses nucleic acid amplification tests on urine or vaginal/endocervical samples. Culture is rarely used. Treatments have included macrolides (eg, azithromycin) and fluoroquinolones (eg, moxifloxacin), but macrolide resistance is increasingly common due to 23S rRNA mutations. Doxycycline is less reliably effective. A test-of-cure is often advised, and treatment may involve partner management.

Epidemiology and public health: Prevalence varies by region and risk group, with higher rates among sexually active adults. Co-infection with other sexually transmitted infections, notably Chlamydia trachomatis, is common. There is no vaccine; prevention relies on safe sex practices and regular screening in high-risk populations. M. genitalium is a focus of study on minimal genomes and antibiotic resistance.