Is Mycoplasma Considered a Sexually Transmitted Infection?
Yes, Mycoplasma genitalium is definitively classified as an emerging sexually transmitted infection (STI) of public health concern by the CDC, while Mycoplasma hominis is associated with sexual activity but not exclusively considered an STI. 1
Mycoplasma Genitalium: A True STI
M. genitalium is unequivocally a sexually transmitted pathogen that causes significant morbidity in both men and women and requires partner notification and treatment to prevent reinfection. 1, 2
Clinical Significance
- M. genitalium causes urethritis in men (particularly non-chlamydial non-gonococcal urethritis), cervicitis in women, and pelvic inflammatory disease (PID) in both sexes. 3, 1, 2
- The infection is spread through sexual contact with an infected person and can be asymptomatic, particularly in males. 2
- In females, M. genitalium may present with nonspecific symptoms including dysuria, vaginal discharge, and/or pelvic pain. 2
Public Health Classification
- The CDC explicitly designates M. genitalium as an emerging STI of public health concern, with formal ICD-10 coding (A63.8) and recommendations for partner notification and treatment. 1
- This classification reflects its contribution to STI syndromes and increasing antimicrobial resistance patterns. 1, 4
Testing Recommendations
- Clinicians should integrate M. genitalium testing into the management of persons with STI syndromes (urethritis, cervicitis, PID) and their sex partners when diagnostic tests are available. 4
- Diagnosis requires nucleic acid amplification tests (NAATs), as the organism is difficult to culture. 5
Mycoplasma Hominis: Associated with Sexual Activity but Not Exclusively an STI
M. hominis occupies a gray zone—it is associated with sexual activity but is not classified as an exclusive STI. 3
Key Distinctions
- M. hominis is part of the altered vaginal flora in bacterial vaginosis (BV), along with anaerobic bacteria and Gardnerella vaginalis. 3
- BV is associated with sexual activity (women who have never been sexually active are rarely affected, and acquisition correlates with multiple sex partners), but it is unclear whether BV results from acquisition of a sexually transmitted pathogen. 3
- Treatment of male sex partners has not been beneficial in preventing BV recurrence, which argues against classifying M. hominis as a traditional STI. 3
Clinical Context
- M. hominis is listed among pathogens associated with pelvic inflammatory disease and endometritis in diagnostic guidelines. 3
- However, its role is as part of polymicrobial vaginal flora disruption rather than as a primary sexually transmitted pathogen. 3
Critical Clinical Pitfalls
Don't Confuse the Two Species
- M. genitalium requires specific STI management including partner notification, treatment, and consideration of antimicrobial resistance. 1, 4, 6
- M. hominis is managed as part of BV treatment when symptomatic, without routine partner treatment. 3
Antimicrobial Resistance Concerns
- M. genitalium has rapidly developing macrolide and quinolone resistance, making azithromycin 1g monotherapy suboptimal. 6
- Treatment failure rates can reach 9.4%, with higher organism loads associated with treatment failure. 7