When Should I Get Mgen Testing for Persistent Cervicitis?

Yes, if you have persistent or recurrent cervicitis (inflammation of the cervix) and standard STI tests—like chlamydia and gonorrhea—are negative, it is time to ask your clinician about testing for Mycoplasma genitalium (often called Mgen).

Mgen is a common sexually transmitted bacterium and one possible explanation for chronic cervical inflammation ^[1]. However, it is not the only potential cause. Before or alongside testing for Mgen, your clinician should also check for reinfection, missed antibiotic doses, Trichomonas vaginalis, bacterial vaginosis, herpes, noninfectious irritation, or pelvic inflammatory disease (PID) ^[2][3][4].

Urgent Warning: If you experience fever, chills, new or worsening lower-abdominal or pelvic pain, vomiting, severe pain during sex, or heavy bleeding, seek medical care immediately. These are red flags for serious conditions like pelvic inflammatory disease (PID) that require prompt assessment.

Why Isn’t Mgen Part of Routine Testing?

Unlike chlamydia and gonorrhea, health guidelines specifically recommend against routinely screening asymptomatic people for Mgen ^[1][5]. Many people carry the bacterium without it causing health problems ^[5]. However, treating asymptomatic cases over the years—particularly with single-dose azithromycin (a type of macrolide antibiotic)—has selected for genetic mutations, making Mgen highly resistant to standard treatments ^[5][6].

Targeted testing is reserved for people with persistent or recurrent symptoms to help guide appropriate, specialized treatment ^[1][7].

How Testing Works

Mgen is very difficult to grow in a standard lab culture, so your clinician will use a Nucleic Acid Amplification Test (NAAT) to detect the bacterium’s genetic material ^[8].

• The Best Sample: The accuracy of the test depends on the specific assay your local laboratory uses. However, a vaginal swab often performs very well and is commonly preferred for people with a cervix ^[8].
• Resistance Testing: If available, laboratories can simultaneously test the sample for macrolide resistance ^[9]. This identifies genetic mutations that make the bacterium resistant to azithromycin ^[10]. Unfortunately, resistance testing is not widely accessible everywhere, including in many parts of the United States ^[11].

Specialized Treatment Approaches

If you test positive, an individualized treatment plan is necessary. Do not reuse leftover antibiotics or share pills with a partner. Mgen often requires a “staged” or “resistance-guided” antibiotic regimen ^[5][11]:

1. Initial Phase: Clinicians often start with a week of doxycycline to lower the bacterial load ^[12].
2. Clearance Phase: This is typically followed by an extended course of azithromycin (if your strain is susceptible) or a different antibiotic like moxifloxacin (if it is resistant) ^[12][1].

Note: The exact medications prescribed will depend on local guidelines, resistance test results, and your medical history. Moxifloxacin has important adverse effects and interactions, so your clinician will need to carefully review whether it is safe for you ^[13].

Considerations for Pregnancy and Partners

• Pregnancy and Breastfeeding: Evidence about Mgen in pregnancy is complex; while some observational studies report associations with adverse outcomes like preterm birth, the direct benefit of routine screening is uncertain ^[14][15]. However, if you are pregnant and have symptoms, contact your obstetric clinician promptly. Key antibiotics used for resistant Mgen (like doxycycline and moxifloxacin) are generally avoided during pregnancy ^[16]. Your clinician will need to carefully balance risks and benefits to choose a pregnancy-safe regimen ^[16]. Breastfeeding safety also requires an individualized discussion with your care team.
• Treating Partners: Studies estimate that 39% to 50% of current sexual partners share the infection ^[13]. Your current partners should be evaluated by a clinician to be tested and treated (or treated based on your positive result if testing isn’t available). To prevent passing the infection back and forth, you and your partner(s) must abstain from all sexual contact until you have both completed treatment and your symptoms have fully resolved. While condoms reduce risk, they do not replace the need for complete abstinence during treatment ^[17].

Following Up (Test of Cure)

If your symptoms completely resolve after completing the recommended treatment, you generally do not need another test ^[5]. However, if symptoms persist, or if local guidelines or pregnancy status require it, your clinician may recommend a “test of cure.”

Timing is critical: A follow-up test should be done no earlier than 3 to 4 weeks (at least 21 days) after you finish your antibiotics ^[18][19]. Testing too early risks a false-positive result because the highly sensitive NAAT can detect residual, harmless genetic material from dead bacteria ^[18]. If your symptoms continue, do not assume you just need more antibiotics; your clinician must comprehensively reassess you for other causes ^[3].