Infectious Diseases

Genital mycoplasmas, Ureaplasma

OVERVIEW: What every clinician needs to know

Pathogen name and classification

Multiple species of the genera Mycoplasma and Ureaplasma can infect the human genitourinary tract. These include M. hominis, M. genitaliumand U. urealyticum.

What is the best treatment?

  • Doxycycline is the treatment of choice for M. hominis and U. urealyticum.Duration and dose vary by site of infection, and are usually incombination with other antibiotics. Examples include doxycycline 100mgorally twice daily for 14 days (as part of a combination regimen forpelvic inflammatory disease), and doxycycline 100mg orally twice dailyfor 7 days for uncomplicated nongonococcal urethritis in men.

  • Azithromycin is the preferred treatment for M. genitalium.Duration and dose vary by site of infection, and are usually incombination with other antibiotics. An example is azithromycin 1g orallyonce for uncomplicated nongonococcal urethritis in men, or forcervicitis in women.

  • M. hominis isresistant to macrolide antibiotics. In some studies, up to 10% ofisolates were resistant to tetracyclines, including doxycycline. Ifdoxycycline cannot be used as first-line therapy, alternatives includeclindamycin or a fluoroquinolone.

  • Clindamycin is not active against Ureaplasma species.

How do patients contract this infection, and how do I prevent spread to other patients?

  • Epidemiology:

    • In adults, colonization with M. hominis, M. genitalium and U. urealyticum is associated with sexual activity.

    • In studies of STD clinic populations, these organisms were more commonly found in patients younger than 50, women and African Americans.

    • In the United States, some studies have also found an association between colonization and lower socioeconomic status.

  • Infection control issues:

    • There is no vaccine available.

    • Post-exposure prophylaxis is not recommended.

What host factors protect against these infections?

  • There is likely importance to both the cellular and humoral immune system responses in controlling genital Mycoplasma and Ureaplasma infections, but the exact mechanisms are not well understood.

  • The organisms cause disease as extracellular parasites attaching to both ciliated and non-ciliated epithelial cells of the genitourinary (GU) tract. Once attached, they may either cause direct destruction or trigger immune mediated damage to the GU tract.

What are the clinical manifestations of infection with these organisms?

  • Associated clinical diseases include pelvic inflammatory disease, cervicitis, urethritis, epididymitis, pyelonephritis, chorioamnionitis, post-partum fever, still birth, and rarely meningitis, brain abscess, endocarditis, wound infections, and bacteremia. Ureaplasma and M. hominis have been associated with bacteremia, pneumonia and meningoencephalitis in neonates.

  • Genital mycoplasma or ureaplasma infection may be asymptomatic in many cases.

  • Urethritis may present with urethral discharge in men, vaginal discharge in women or urethral irritation or dysuria in either men or women.

  • Epididymitis most often presents as unilateral warmth, tenderness and swelling of the epididymis overlying the testis within the scrotum. Patients may describe discomfort with ejaculation.

  • Cervicitis may result in vaginal discharge, pelvic pain or dyspareunia. On pelvic examination, a swab placed into the cervical os will reveal discharge, and wet mount will have copious white blood cells.

  • Pelvic inflammatory disease is a clinical diagnosis. Many cases may be asymptomatic or have only minimal symptoms. Classic findings include fever, pelvic or low abdominal pain and one or more of the following on pelvic exam: uterine, cervical or adnexal tenderness.

  • The clinical manifestations of pyelonephritis include fever, dysuria, abdominal and/or back pain, and tenderness to percussion of the costovertebral angle on the affected side. Hematuria may be present.

  • Pregnant women with chorioamnionitis present with fever and abdominal or pelvic pain. Uterine tenderness is present on examination.

What common complications are associated with infection with this pathogen?

  • Complications include pyelonephritis, pelvic inflammatory disease, postpartum fever, and still birth. More rare complications include meningitis, brain abscess, endocarditis, wound infections, and bacteremia. Ureaplasma and M. hominis have been associated with bacteremia, pneumonia and meningoencephalitis in neonates.

How should I identify these organisms?

  • Sampling from the affected organ system for specialized culture would yield the best results. However, culture is not widely available.

  • These organisms do not have cell walls, and therefore it is not possible to perform gram staining on them.

  • Culture is highly specialized, and available in limited laboratories. Samples must be immediately placed into broth before they dry out. Initial pH distinguishing plates, which help differentiate these organisms from M. pneumoniae, are followed by blood agar plates which are kept in a 95% nitrogen and 5% CO2 environment. The M. hominis colonies have a characteristic "fried egg" appearance.

PCR assays for genital Mycoplasma and Ureaplasmaare not commercially available. One study showed that sensitivity using vaginal swabs was 86%.

How do these organisms cause disease?

  • Mycoplasmas attach to the exterior of both ciliated and non-ciliated epithelial cells. Cell damage may be mediated either through direct effects (hydrogen peroxide for instance) or may be immune mediated, but the exact contribution of each is not well known.

WHAT’S THE EVIDENCE for specific management and treatment recommendations?

Haggerty, CL, Taylor, BD. "Mycoplasma genitalium: an emerging cause of pelvic inflammatory disease". Infect Dis Obstet Gynecol. vol. 2011. 2011. pp. 959816.

(A review of the evidence for an association between M. genitalium and PID.)

Larsen, B, Hwang, J. "Mycoplasma, Ureaplasma, and adverse pregnancy outcomes: a fresh look". Infect Dis Obstet Gynecol. 2010.

(Reviews the effect of these infections in pregnancy.)

Vandepitte, J, Bukenya, J, Hughes, P, Muller, E, Buvé, A, Hayes, R, Weiss, HA, Grosskurth, H. "Clinical characteristics associated with Mycoplasma genitalium infection among women at high risk of HIV and other STI in Uganda". Sex Transm Dis.. vol. 39. 2012 Jun. pp. 487-91.

(Further refines growing data on epidemiology of M. genitalium.)

Ito, S, Tsuchiya, T, Yasuda, M, Yokoi, S, Nakano, M, Deguchi, T. " Prevalence of genital mycoplasmas and ureaplasmas in men younger than 40 years-of-age with acute epididymitis". Int J Urol.. vol. 19. 2012 Mar. pp. 234-8.

(Study of association with genital tract disease in men.)
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