Mycoplasma genitalium is a bacterium that can cause sexually transmitted infections (STIs) and urogenital infections. This article explores its global prevalence, associated health concerns, and how it is detected and managed.
Understanding Mycoplasma Genitalium
Mycoplasma genitalium is among the smallest known self-replicating bacteria. It lacks a cell wall, making it naturally resistant to certain antibiotics like penicillin that target cell wall formation. The bacterium primarily infects the urogenital tract. In women, this includes the vagina, womb, fallopian tubes, and urethra; in men, it typically affects the urethra and epididymis. Transmission occurs through sexual contact, including unprotected vaginal and anal sex.
Global and Regional Prevalence
The prevalence of Mycoplasma genitalium varies across populations and geographic regions. In higher-income countries, estimates suggest 1% to 2% of adults may carry the infection. For instance, UK studies reported a prevalence of approximately 1.2% in men and 1.3% in women aged 16 to 44 years. In the United States, about 1.1% of men and 1.4% of women aged 18 to 27 years have been found infected.
Prevalence rates are significantly higher in specific risk groups, such as individuals attending STI clinics, where rates can range from 10% to over 20%. For example, US STI clinics reported prevalence at 16.1% in women and 17.2% in men. Many infections are asymptomatic, meaning individuals may carry the bacterium without symptoms. This asymptomatic nature, coupled with limited routine testing, means true prevalence might be underestimated.
Associated Health Concerns
If left untreated, Mycoplasma genitalium infections can lead to various health issues. In men, the infection commonly causes urethritis, an inflammation of the urethra. Symptoms can include pain during urination, discharge from the penis, pain during ejaculation, or itching. Untreated infections in men may also progress to epididymo-orchitis, a painful swelling of the testicle and the tube that stores sperm.
For women, Mycoplasma genitalium can cause cervicitis, an inflammation of the cervix, leading to unusual vaginal discharge, pain during sexual intercourse, or bleeding between periods. A more serious complication is pelvic inflammatory disease (PID), an infection of the womb, fallopian tubes, and ovaries. PID can result in abdominal pain, fever, and may contribute to tubal infertility or increase the risk of ectopic pregnancy. Both men and women may also experience sexually acquired reactive arthritis.
Detection and Management
Diagnosing Mycoplasma genitalium infection presents challenges because the bacterium grows slowly in laboratory cultures. Therefore, Nucleic Acid Amplification Tests (NAATs) are the primary and most reliable method for detection. These tests identify the bacterium’s genetic material from samples such as urine or swabs collected from the vagina, cervix, or urethra. NAATs provide accurate and relatively fast results, often within 24 to 48 hours.
Treatment for Mycoplasma genitalium typically involves antibiotics, but managing the infection has become increasingly complex due to rising antibiotic resistance. Resistance to azithromycin, a commonly used first-line antibiotic, is widespread, with rates often exceeding 50% in many regions and high-risk populations. Moxifloxacin serves as a second-line treatment option, but resistance to this antibiotic is also on the rise in some areas.
To improve treatment success, resistance-guided therapy, which involves testing for antibiotic resistance before selecting a treatment, is increasingly recommended when available. Doxycycline is often used as an initial therapy or pre-treatment to help reduce the bacterial load before other antibiotics are administered. In cases where common antibiotics fail, alternative treatments like pristinamycin or minocycline may be considered, though their availability can be limited.