The main Mycoplasma species that infect the human urogenital tract include Ureaplasma urealyticum (UU), Mycoplasma hominis (MH), and Mycoplasma genitalium (MG). These pathogens are common causes of vaginitis and cervicitis in women.
Related Factors for Disease Onset
Mycoplasma are the smallest microorganisms capable of independent survival and lack a cell wall. They are commonly found in the urogenital tract of women and adhere to the mucosa of the urogenital tract via surface proteins. Co-infection with Chlamydia trachomatis is frequently observed.
Modes of Transmission
Mycoplasma are present in the vagina, at the cervical os, surrounding the external urethral opening, and in urine. Sexual contact is the primary mode of transmission. Vertical transmission can occur via the placenta or through ascending infection in the reproductive tract, leading to intrauterine infection. Infection of the fetus may also occur during delivery through a contaminated birth canal.
Effects on Mother and Child
The association between Mycoplasma infection and adverse pregnancy outcomes remains controversial. Some evidence suggests that Mycoplasma can cause intra-amniotic infection. However, vaginal Mycoplasma colonization during pregnancy does not exhibit a significant correlation with the occurrence of low birth weight, premature rupture of membranes, or preterm birth. If ascending lower genital tract Mycoplasma infection to the uterine cavity is suspected to cause chorioamnionitis and preterm labor, sampling from the upper genital tract is recommended to confirm the diagnosis.
Clinical Manifestations
Mycoplasma hominis primarily causes vaginitis, cervicitis, and salpingitis. Ureaplasma urealyticum is mainly associated with non-gonococcal urethritis, while Mycoplasma genitalium is commonly linked to cervicitis, endometritis, and pelvic inflammatory disease (PID). Mycoplasma, particularly Ureaplasma urealyticum, often exhibits colonization in the urogenital tract, coexisting with the host without causing infection. Opportunistic infections tend to occur under certain conditions.
Diagnosis and Differential Diagnosis
Testing for Mycoplasma should be considered in women with recurrent cervicitis or PID. Laboratory tests include:
- Culture Method: Mycoplasma hominis or Ureaplasma urealyticum can be detected through culture, but Mycoplasma genitalium grows extremely slowly and is almost impossible to diagnose via in vitro culture.
- Nucleic Acid Testing: This method has higher sensitivity than culture and can also determine the Mycoplasma species.
- Serological Testing: Levels of specific antibodies in asymptomatic women are typically low, but a significant increase in antibody levels may occur after reinfection.
Differentiation is required from other pathogens that cause vaginitis, cervicitis, urethritis, and PID, especially Chlamydia trachomatis and Neisseria gonorrhoeae.
Treatment
Asymptomatic carriers with positive tests for Mycoplasma hominis or Ureaplasma urealyticum do not require treatment. Symptomatic individuals may be treated with:
- Doxycycline 0.1 g orally twice daily for 7 days.
- Azithromycin 1 g orally as a single dose, or 0.25 g orally once daily (with an initial double dose) for 5–7 days.
- Levofloxacin 0.5 g orally once daily for 7 days.
- Moxifloxacin 0.4 g orally once daily for 7–14 days.
For patients with concurrent PID, treatment duration is extended to 14 days.
Pregnant women with asymptomatic lower genital tract Mycoplasma colonization do not require treatment, but symptomatic individuals are treated with azithromycin 1 g as a single dose. An alternative is erythromycin 0.5 g orally twice daily for 14 days. In cases of neonatal infection, erythromycin at 25–400 mg/kg/day, administered by intravenous infusion in four divided doses, or orally, for 7–14 days, is recommended.
Follow-Up
There is no established optimal follow-up protocol for Mycoplasma infections. Patients with confirmed Mycoplasma infection are typically followed up after treatment. For culture-based testing, follow-up is conducted 2 weeks post-therapy cessation. For nucleic acid testing, follow-up is performed 4 weeks after stopping the medication.