What is Mycoplasma genitalium?

What is Mycoplasma genitalium?

Mycoplasma genitalium is a sexually transmitted bacterial pathogen that causes urethritis in men and cervicitis, pelvic inflammatory disease, and potentially infertility in women, and is now recognized by the CDC as an emerging STI of public health concern. 1

Organism Characteristics

• M. genitalium is the smallest prokaryote capable of independent replication, belonging to the class Mollicutes and lacking a cell wall 2
• First isolated in 1981 from urethral swabs of men with urethritis 2, 3
• It is a fastidious organism that grows poorly or slowly in culture, making diagnosis challenging 4

Clinical Significance in Men

• M. genitalium is an established cause of non-gonococcal urethritis (NGU), accounting for 23-55% of NGU cases in some populations 5
• It is particularly implicated in persistent and recurrent NGU cases 4
• Complications include epididymitis and Reiter's syndrome 5
• The organism has been implicated in approximately one-third of nonchlamydial NGU cases 5

Clinical Significance in Women

• M. genitalium causes cervicitis, endometritis, and pelvic inflammatory disease (PID) in women 1, 6
• Evidence strongly suggests it contributes to infertility through ascending infection 6, 4
• It increases susceptibility to HIV infection 3, 7
• The organism may also be associated with adverse pregnancy outcomes, though evidence is less clear 7

Epidemiology and Prevalence

• Prevalence ranges from 0.5-10% in the general population and 20-40% in women with sexually transmitted infections 3
• Among over 27,000 women screened worldwide, overall prevalence was 7.3% in high-risk populations and 2.0% in low-risk populations 6
• Prevalence rates fall between those of Chlamydia trachomatis and Neisseria gonorrhoeae in the general population 6
• Higher prevalence is found in patients attending sexual health clinics and in men with NGU 2

Asymptomatic Infection - A Critical Pitfall

• The majority of infected individuals remain asymptomatic and may clear infection without developing disease 2
• M. genitalium can act as a "stealth pathogen" in the female reproductive tract, causing no symptoms while potentially causing damage 3
• Because most infections are asymptomatic, routine screening is not currently recommended 2, 7

Diagnostic Considerations

• Diagnosis is performed exclusively using nucleic acid amplification tests (NAATs) due to poor growth in culture 4
• Testing should include detection of macrolide resistance-mediating mutations to guide treatment 2
• Specific diagnostic tests for M. genitalium were historically not indicated in routine practice, though this is changing 5

Treatment Challenges

• Widespread antimicrobial resistance has emerged due to syndromic management without specific testing 2
• Macrolide resistance has increased significantly, with cure rates falling below 50% in some studies with single-dose azithromycin 3
• Few antimicrobial classes have activity against M. genitalium, raising concern about untreatable strains 2
• The CDC recommends considering M. genitalium treatment in patients with persistent symptoms after standard therapy 7

Public Health Implications

• The CDC considers M. genitalium an emerging STI of public health concern 1
• Partner notification and treatment are recommended to prevent reinfection 1
• National and international public health surveillance is vital for monitoring changing epidemiology and resistance patterns 2
• The ICD-10 code A63.8 is recommended for M. genitalium infection 1