STIs
Mycoplasma hominis PCR (swab)
PCR test for Mycoplasma hominis in a vaginal swab; often present without symptoms, so a positive result says little.
What it measures
Mycoplasma hominis is a small bacterium without a cell wall that is found in the genital organs of many healthy people without causing symptoms (carriership). The bacterium can be transmitted through sex, but is not counted as an STI, because it has not been shown to cause disease in adults. In women, it is mainly found in larger amounts with bacterial vaginosis (a disturbance of the normal bacteria in the vagina). The PCR looks for genetic material of the bacterium in a self-collected vaginal swab and does not say whether the bacterium causes symptoms.
- Presence of Mycoplasma hominis in the vagina; this is usually carriership without symptoms
Positive
A positive result means that the bacterium is present. This is common in people without symptoms and usually does not mean disease. According to a position statement of the European STI guidelines editorial board (IUSTI, 2018), there is no good evidence that Mycoplasma hominis causes inflammation or infertility in adult men or non-pregnant women, and it has not been shown that treatment does more good than harm. Treating a positive result without symptoms is therefore not needed. With symptoms such as discharge that smells different, the doctor mainly looks at bacterial vaginosis and at real STIs.
Negative
A negative result means that the bacterium was not found. Because Mycoplasma hominis also occurs in healthy people and is not a proven pathogen, a negative result has little meaning for your health. This result neither explains nor rules out vaginal symptoms; tests for, among others, chlamydia, gonorrhea, trichomonas and bacterial vaginosis are intended for that.
If your result is abnormal
With a positive result without symptoms, no treatment or follow-up check is needed according to the European recommendation. With symptoms, the GP first looks for other causes, such as chlamydia, gonorrhea, trichomonas or, in women, bacterial vaginosis. Mycoplasma hominis is not notifiable.
Reliability
The PCR detects the bacterium reliably, but a positive result does not distinguish between carriership and an infection that causes symptoms. Mycoplasma hominis is not a proven pathogen: the evidence that this bacterium causes urethritis or other symptoms is insufficient. As a result, a positive result says little, both in people without symptoms and in people with symptoms.
Limitations
- A positive result does not say whether the bacterium causes symptoms; many women without symptoms also carry the bacterium.
- The amount of bacteria is strongly linked to bacterial vaginosis, which can itself be the cause of symptoms; the test is not a reliable test for bacterial vaginosis.
- Mycoplasma hominis is naturally insensitive to some of the common antibiotics and often does not disappear permanently after treatment.
- With self-collection, too little material may end up on the swab, for example if it was not inserted far enough or for too short a time; this can give a falsely negative result.
How common is this
How often Mycoplasma hominis occurs in the Netherlands is not known, because it is not routinely tested for. In international research using PCR, the bacterium was found in 3 to 15 percent of sexually active women who were not pregnant. In men who visited an STI clinic, this was 2 to 4 percent; most people with the bacterium do not become ill.
Who is this useful for
The result usually does not explain symptoms, because the bacterium also occurs in many healthy people. Vaginal symptoms more often fit bacterial vaginosis, chlamydia, gonorrhea or trichomonas. This test is not suitable for questions about pregnancy or fertility.
Downsides and risks
- A positive result can lead to unnecessary treatment with antibiotics, with a risk of side effects and of resistance in this bacterium and in other bacteria, including the causes of real STIs.
- A positive result can wrongly give the idea that you have an STI, resulting in worry or tension in a relationship.
Sources
- Horner e.a. Should we be testing for urogenital Mycoplasma hominis, Ureaplasma parvum and Ureaplasma urealyticum in men and women? Standpunt van de European STI Guidelines Editorial Board (IUSTI), J Eur Acad Dermatol Venereol 2018
- Multidisciplinaire Richtlijn Seksueel overdraagbare aandoeningen (2024), module B1 Urethritis
- Thuisarts.nl: Ik wil een soa-test doen
Always discuss an abnormal result with your GP. If a result is strongly abnormal, we try to reach you as soon as possible. Read your result yourself as well and contact your GP if in doubt. A test does not make a diagnosis. Read more about risks and results