Mycoplasma genitalium is a sexually transmitted infection (STI) that often goes unnoticed due to its frequently silent nature. If left untreated, it can lead to serious health issues, particularly affecting reproductive health in women. This bacterium is distinct from more commonly known STIs and has become a growing concern in public health. Understanding this infection is important for prevention and timely management.
Understanding Mycoplasma genitalium
Mycoplasma genitalium (MG) is a bacterium that can cause sexually transmitted infections. Unlike many other bacteria, MG lacks a cell wall, which means common antibiotics that target cell wall formation, such as penicillins and cephalosporins, are ineffective against it. This structural difference makes MG challenging to treat.
The bacterium is primarily transmitted through sexual contact, including vaginal and anal intercourse. An infected person can pass the bacterium to others even without showing symptoms, contributing to its silent spread.
MG is an emerging concern, recognized since the 1980s. Its prevalence varies, but it is generally found in about 2% of adults. Some studies show MG can be more common than chlamydia and gonorrhea in certain populations, highlighting its increasing significance as an STI.
Recognizing the Symptoms and Complications
Mycoplasma genitalium infections frequently present without noticeable symptoms, making them difficult to detect and contributing to their silent spread. This asymptomatic nature is a challenge in controlling the infection, as individuals may unknowingly transmit it. When symptoms do appear, they can often be mistaken for other sexually transmitted infections or urinary tract infections, complicating diagnosis.
In women, MG can cause inflammation of the cervix (cervicitis) and inflammation of the urethra (urethritis). Symptoms may include unusual vaginal discharge, burning or pain during urination, abdominal or pelvic pain, and discomfort during sexual intercourse. Bleeding between periods or after sexual intercourse can also occur.
Untreated MG infections in women can lead to more serious complications affecting reproductive health. These include pelvic inflammatory disease (PID), an infection of the reproductive organs such as the uterus, fallopian tubes, and ovaries. PID can result in chronic pelvic pain, scar tissue formation that blocks fallopian tubes, and can increase the risk of ectopic pregnancy (a pregnancy outside the uterus) and infertility. MG infection has also been associated with an increased risk of preterm birth and spontaneous abortion.
In men, MG commonly causes urethritis, leading to symptoms such as watery discharge from the penis, burning or pain during urination, and pain or itching in the urethra. Some men may also experience pain during ejaculation or pain in the testicles. Inflammation of the epididymis (epididymitis) can occur, causing pain and swelling in the testicles. For individuals engaging in anal sex, MG can also cause proctitis (inflammation of the rectum), leading to discharge or discomfort.
Diagnosing and Treating Mycoplasma genitalium
Diagnosing Mycoplasma genitalium presents challenges because the bacterium cannot be grown using standard laboratory culture methods. Diagnosis relies on specialized tests called nucleic acid amplification tests (NAATs), such as PCR. These tests detect the genetic material of MG in samples, which can be collected from urine, vaginal swabs, cervical swabs, urethral swabs, or rectal swabs. However, NAATs for MG are not always routinely performed, which can delay diagnosis.
Treatment for MG involves specific antibiotics, but antibiotic resistance significantly complicates management. Historically, azithromycin was a common first-line treatment, but resistance to macrolide antibiotics has become widespread globally. The overuse of single-dose azithromycin has contributed to this resistance.
Due to increasing resistance, a single 1-gram dose of azithromycin is no longer recommended for MG. Current treatment guidelines often recommend a two-stage approach, ideally guided by resistance testing. This involves initial treatment with doxycycline for seven days. Following doxycycline, if macrolide resistance testing is available and the infection is sensitive, a high-dose, extended course of azithromycin may be used.
If macrolide resistance is confirmed or suspected, or if resistance testing is unavailable, moxifloxacin is often recommended as the subsequent treatment after doxycycline. Moxifloxacin is a fluoroquinolone antibiotic, and while generally effective, resistance to it is also emerging. “Resistance-guided therapy” aims to tailor treatment based on the specific resistance profile of the MG strain, which has shown cure rates over 90%.
After completing treatment, a retest to confirm eradication of the infection is important, typically 14 to 21 days after the last dose of antibiotics. Prevention of MG, like other STIs, involves practicing safe sex, such as consistent and correct condom use, which significantly reduces the risk of transmission.