References UK clinical guidance from the NHS, the British HIV Association (BHIVA), and the British Association for Sexual Health and HIV (BASHH). Last updated: April 2026.
Testing for Mycoplasma genitalium (Mgen) uses NAAT — nucleic acid amplification testing — to detect this increasingly recognised STI. Mgen can cause urethritis, cervicitis and pelvic inflammatory disease, often silently. Modern tests can also check for antibiotic resistance, helping guide treatment. Testing isn’t routinely included in all STI screens, so you may need to ask.
Here’s what to know.
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What the Test Detects
| What It Identifies | Detail |
|---|---|
| Mgen presence | Active infection with the bacterium |
| Macrolide resistance mutations | Helps choose the right antibiotic |
Sample Types
- Urine (men or women)
- Vaginal swab (self-collected or clinician)
- Throat swab (if oral sex)
- Rectal swab (if anal sex)
When to Test
- Symptoms of urethritis or cervicitis
- Persistent symptoms after standard STI testing
- Partner has tested positive
- As part of investigation for pelvic inflammatory disease
- As recommended by your sexual health team
Symptoms
| In Men | In Women |
|---|---|
| Urethral discharge | Unusual vaginal discharge |
| Burning on urination | Bleeding between periods or after sex |
| Often asymptomatic | Pelvic pain |
| Often asymptomatic |
Treatment
Treatment depends on whether macrolide resistance is present:
- No resistance — doxycycline 7 days then azithromycin (1g then 500mg daily for 2 days)
- Resistance present — doxycycline 7 days then moxifloxacin 400mg daily for 10 days
Test of Cure
Unlike most STIs, Mgen treatment is followed by a test of cure 3-5 weeks after completing antibiotics. This confirms the infection has cleared. If not, second-line treatment is used.
Why It Matters
- Mgen is increasingly common
- Antibiotic resistance is rising
- Untreated Mgen can cause PID and infertility
- Proper testing and resistance profiling matter for effective treatment
Where to Test
- NHS sexual health clinics that offer Mgen testing
- Some home test kits
- Specialist clinics
Read more: Mycoplasma genitalium overview | Curing Mgen | Discharge and STIs
Frequently Asked Questions
Is Mgen included in standard STI tests?
Not always. Ask your service if you want it included.
Is Mgen always treated?
Treatment is usually offered when symptoms are present.
What is test of cure?
A follow-up test to confirm the infection has cleared after treatment.
Related reading
- Abnormal Genital Discharge and Chlamydia
- Can Mycoplasma Genitalium Be Cured?
- Can You Get Chlamydia From Kissing?
- Can You Have Chlamydia and Test Negative?
- Chlamydia and Gay Men: What to Know
Sources
- NHS — Sexual health conditions
- BASHH — UK clinical guidelines for STI management
- British HIV Association (BHIVA) — HIV treatment guidelines
- Terrence Higgins Trust — sexual health information
- UK Health Security Agency — STI surveillance data
Steve Page is a recognised expert on Sexually Transmitted Diseases (STDs) and STD treatments, having published numerous articles in peer-reviewed journals and presented his research at conferences around the world. He has an in-depth understanding of the latest medical research on STDs, and is an advocate for the development of new treatments and protocols to improve the health of those affected. In addition to his research, he has dedicated his career to understanding the causes and symptoms of STDs, as well as how to best treat those impacted.
