Skip to content

The protective role of the vaginal microbiome

 

The vaginal microbiome can play a protective role for a woman, or it can become imbalanced and cause inflammation, unwanted symptoms, and impact various aspects of urogenital health. The vaginal microbiome is one of many communities of microbes in the human body, others include the gut, mouth and the skin. A healthy vaginal microbiome is dominated by lactobacillus species, and less commonly bifidobacterium, and provides the first line of defence against invading pathogens.1 Yeast and viruses may be found in a vaginal microbiome too, but lactobacillus and other health factors should keep these at bay.

The vaginal microbiome is also dynamic. It is influenced by factors such as age, oestrogen status, ethnicity, sexual partners, hygiene, lifestyle and diet. Hence a woman’s microbiome status will likely change throughout her lifetime, experiencing periods of balance and periods of dysbiosis (imbalance). Beneficial bacteria help maintain mucous barrier integrity in the vaginal canal and lactobacilli can induce host defence against pathogens through the formation of micro-colonies that attach to epithelial cell receptors and form a physical barrier to pathogen attachment.2

Dysbiosis of the vaginal microbiome refers to an imbalance in the natural bacterial community. Specifically, a disruption to the normal dominance of beneficial bacteria lactobacilli, where a highly diverse state of opportunistic anaerobic and aerobic microbes takes hold instead. Opportunistic bacteria likely translocate from the gut or they may come from a partner. In a dysbiotic vaginal microbiome, microbial diversity is accompanied with increased mucosal inflammation and immune cell activation within the vaginal tract.3 In some cases, dysbiosis can be symptomatic, and present with symptoms such as discharge, burning and an unusual odour.

Aerobic Vaginitis (AV) and Vulvovaginal Candidiasis (VVC) tend to present with symptoms in women, but Bacterial Vaginosis (BV) can be asymptomatic in up to 50% of women.4 Dysbiosis, characterised by loss of lactobacillus dominance and increased microbial diversity, has been linked to an increased risk of:

In a balanced microbiome, we expect to see plump, strong tissues due to an intact and well lubricated epithelial lining. In addition, the environment remains acidic between pH 3.7 - 4.5, suppressing opportunistic microbe growth. In a dysbiotic environment, we tend to see generalised inflammation, including sore, sensitive tissues as a result of a loss of barrier integrity and reduced mucus levels. An unusual odour may be experienced due to amine producing opportunistic bacteria, and an unusual, heavier discharge, similarly as a result of increased opportunistic bacteria. 

Our qPCR testing methodology, Precision Microbiome Profiling, PMP™ is a proprietary technology relying on highly parallelised singleplex qPCR-based designed for microbiome analysis. It offers high sensitivity, quantitative accuracy, speed and reliability, while uniquely enabling the detection of >50 distinct microbial taxa. In addition to returning accurate microbiome profiles, PMP™ offers absolute quantification of each targeted microorganism, alongside quantification for the overall bacterial load in a specimen. With the precision and accuracy offered by PMP™, healthcare providers can gain deeper insights into microbial imbalances.

 

REFERENCES 1. Schwecht I, Nazli A, Gill B, Kaushic C. Lactic acid enhances vaginal epithelial barrier integrity and ameliorates inflammatory effects of dysbiotic short chain fatty acids and HIV-1. Sci Rep. 2023 Nov 16;13(1):20065. 2. Valeriano V.D, Lahtinen E, Lahtinen E, Hwang I, Zhang Y, Du Y, Schuppe-Koistinen I. Vaginal dysbiosis and the potential of vaginal microbiome-directed therapeutics. Frontiers in Microbiomes. 2024 Oct 11; Vol 3. 3. Valeriano V.D, Lahtinen E, Lahtinen E, Hwang I, Zhang Y, Du Y, Schuppe-Koistinen I. Vaginal dysbiosis and the potential of vaginal microbiome-directed therapeutics. Frontiers in Microbiomes. 2024 Oct 11; Vol 3. 4. National Health Service. Bacterial vaginosis. NHS website. Available from: https://www.nhs.uk/conditions/bacterial-vaginosis/. Accessed 30 Jan 2025. 5. Thomas L. What role do microbiomes play in urinary tract infections? News-Medical. Last updated Aug 31, 2023. Available at: https://www.news-medical.net/health/What-Role-do-Microbiomes-Play-in-Urinary-Tract-Infections.aspx. Accessed 30 Jan 2025. 6. van de Wijgert JHHM, Jespers V. The global health impact of vaginal dysbiosis. Res Microbiol. 2017 Nov-Dec;168(9-10):859-864. doi: 10.1016/j.resmic.2017.02.003. 7. Ntuli L, Mtshali A, Mzobe G, Liebenberg LJ, Ngcapu S. Role of Immunity and Vaginal Microbiome in Clearance and Persistence of Human Papillomavirus Infection. Front Cell Infect Microbiol. 2022 Jul 7;12:927131. 8. Hong X, Zhao J, Yin J, Zhao F, Wang W, Ding X, Yu H, Ma X, Wang B. The association between the pre-pregnancy vaginal microbiome and time-to-pregnancy: a Chinese pregnancy-planning cohort study. BMC Med. 2022 Aug 1;20(1):246. 9. Ricci S, De Giorgi S, Lazzeri E, Luddi A, Rossi S, Piomboni P, De Leo V, Pozzi G. Impact of asymptomatic genital tract infections on in vitro Fertilization (IVF) outcome. PLoS One. 2018 Nov 16;13(11):e0207684. 10. Mendz GL. The Vaginal Microbiome during Pregnancy in Health and Disease. Appl. Microbiol. 2023, 3, 1302-1338.  11. Cutoiu A, Boda D. An overview regarding the relationship between Mollicutes, infertility and antibiotic resistance (Review). Biomed Rep. 2024 Jun 17;21(2):119. 12. Group B Strep Support. GBS incidence. Group B Strep Support. Available from: https://gbss.org.uk/professional-resources/gbs-incidence/. Accessed 30 Jan 2025. 13. Zizolfi B, Foreste V, Gallo A, Martone S, Giampaolino P, Di Spiezio Sardo A. Endometriosis and dysbiosis: State of art. Front Endocrinol (Lausanne). 2023 Feb 20;14:1140774. 14. Taylor M, Jenkins SM, Pillarisetty LS. Endometritis. [Updated 2023 Oct 26]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2025 Jan-. Available from: https://www.ncbi.nlm.nih.gov/books/NBK553124/ 15. Taylor, M., Jenkins, S. M., and Pillarisetty, L. S. “Endometritis.” StatPearls, StatPearls Publishing, 26 Oct. 2023, https://www.ncbi.nlm.nih.gov/books/NBK553124/. Accessed 24 Mar 2025. 16. MacPhee RA, Miller WL, Gloor GB, McCormick JK, Hammond JA, Burton JP, Reid G. Influence of the vaginal microbiota on toxic shock syndrome toxin 1 production by Staphylococcus aureus. Appl Environ Microbiol. 2013 Mar;79(6):1835-42. 

Pelvic Relief is the trading name of Elgenia Health Ltd, a company registered in England and Wales under Company Number 09833237 and whose Registered Address is at Upper Brockington, Bredenbury, Bromyard, Herefordshire HR7 4TH, VAT Number 227118426. ©Elgenia Health Ltd, 2025. Pelvic Relief® is a registered trade mark of Elgenia Health Ltd.