Megasphaera 1 positive? What your result means
Megasphaera 1 (also written Megasphaera type 1 or Megasphaera-1) is one of the most specific signs of bacterial vaginosis (BV). If it shows up on your swab result, your vaginal microbiome has most likely tipped into BV: common, treatable, and worth taking to a healthcare practitioner.
Megasphaera 1 positive: what it means and what to do
A positive result means Megasphaera 1 was found in your swab. It is rarely present without BV, so it is a strong sign that your vaginal microbiome has shifted into bacterial vaginosis.
Read it with the rest of your report. The pattern matters more than any single organism: Megasphaera 1 alongside low Lactobacillus and other BV markers such as BVAB2 or Gardnerella points clearly to BV. If Megasphaera 1 is not detected and the other BV organisms are low, that is reassuring.
- It is not an STI. BV is an imbalance of the vaginal bacteria, not a sexually transmitted infection, although sex can affect the balance.
- It is common and treatable. BV affects roughly a quarter of women of reproductive age. Take your result to a healthcare practitioner, who can advise on treatment.
- Act on it if you are pregnant. BV matters more in pregnancy, so let your doctor or midwife know about the result.
- If BV keeps coming back, testing again after treatment shows whether the BV organisms have cleared and your Lactobacillus has recovered.
What is Megasphaera 1?
Megasphaera type 1 is an anaerobic bacterium discovered through DNA-based research into bacterial vaginosis. It is one of the most BV-specific organisms identified to date.
It is a leading molecular marker of BV. Research has shown that detecting either Megasphaera type 1 or BVAB2 predicts bacterial vaginosis with very high accuracy, and the two together are among the strongest molecular signals available. Because Megasphaera type 1 cannot be cultured, the only practical way to detect it is molecular testing such as PCR.
Like BVAB2, it is invisible to the older microscope-based approach to BV, which is one of the clearest illustrations of why molecular panels detect more than a stained smear can. Its strong association with BV, and its rarity in women without it, make it a valuable part of a modern panel.
Why Megasphaera type 1 is worth measuring
Among the many organisms found in BV, a handful stand out for how specifically they point to the condition. Megasphaera type 1 is one of them.
Highly specific to BV
It is rarely present without BV, so detecting it is a strong, reliable pointer to genuine dysbiosis.
Molecular detection only
It cannot be grown in standard cultures, so PCR is the only practical way to know whether it is present.
A top diagnostic signal
Paired with BVAB2 it predicts BV with very high accuracy, which is why both feature on the panel.
Molecular BV testing in South Africa
Bacterial vaginosis affects roughly a quarter of reproductive-age women worldwide, and in South Africa it is also linked to higher HIV risk. Markers like Megasphaera type 1 are only detectable with molecular testing, which is not routinely offered in busy clinics, so affordable PCR testing without a referral gives a far more precise answer.
Find out why it returns
If BV keeps coming back after treatment, a panel shows which organisms are still present, which helps explain the pattern.
Name the cause
Discharge or odour that will not settle is worth identifying precisely rather than treating blind.
No referral, three cities
Walk in at Observatory in Cape Town, Hillcrest in Durban or Parktown North in Johannesburg, or test at home anywhere in South Africa.
The BV Microbiome Test
R1,609 17-target PCR panelWhether you want a first test, or want to check that BV has cleared after treatment, Epicentre's BV Microbiome Test is a 17-target PCR panel that measures Megasphaera 1 alongside BVAB2, Gardnerella, your protective Lactobacillus and the other BV-associated organisms. No doctor's referral, and you collect the sample yourself in private.
- Protective Lactobacillus levels, so you can see whether your natural defences are intact.
- Megasphaera 1 and BVAB2, two of the most BV-specific markers, which only molecular testing can detect.
- BV-associated bacteria, such as Gardnerella vaginalis and Atopobium vaginae, the organisms that take over when Lactobacillus falls.
- Group B Streptococcus, which matters in pregnancy.
- You collect the swab yourself, in private, at a branch or at home, with guidance if you want it.
If I had to pick a couple of organisms that most reliably tell me BV is present, Megasphaera type 1 and BVAB2 would be near the top. Neither shows up under a microscope, which is exactly why molecular testing matters.
What testing can and cannot tell you
A microbiome test maps which organisms are present and in what balance; it is not a diagnosis on its own.
- The result describes your vaginal flora at one point in time, which can shift with your cycle, sex, antibiotics and hormones.
- It does not replace a clinical assessment. Use it to inform a conversation with a healthcare practitioner.
- If you have severe pain, fever, or symptoms in pregnancy, seek medical care rather than waiting for a result.
- PCR results take 5 to 7 working days.
Megasphaera 1: quick answers
Vaginal microbiome testing in Cape Town, Durban and Johannesburg
The BV Microbiome Test is available at all three Epicentre walk-in labs: Observatory in Cape Town, Hillcrest in Durban and Parktown North in Johannesburg. Walk in, or book online first. You collect the swab yourself, in private.
Other organisms in the panel
Sources
- Fredricks DN et al. Molecular identification of bacteria associated with bacterial vaginosis. N Engl J Med. 2005.
- BV candidate bacteria: associations with BV and behavioural practices. PLOS One. 2012.
- Coleman JS, Gaydos CA. Molecular diagnosis of bacterial vaginosis: an update. J Clin Microbiol. 2018.
- Shipitsyna E et al. Composition of the vaginal microbiota: sensitive and specific molecular diagnosis of BV. PMC. 2013.
Medically reviewed by Dr Samantha Naidoo, MB ChB, FCP (SA), Medical Director at Epicentre Walk-In Labs. Reviewed 9 June 2026. This article is general health information, not a medical diagnosis. Epicentre Aids Risk Management (Pty) Ltd provides diagnostic laboratory testing and does not provide diagnoses, treatment or prescriptions to the public; results are intended to inform discussions with a registered healthcare practitioner.
Check your BV markers with one swab
The BV Microbiome Test detects Megasphaera and your full vaginal flora from one self-collected swab. Walk in at Observatory, Hillcrest or Parktown North, or order a discreet home kit.
