The Vaginal microbiome - yes Yes YES!
You've probably heard about the microbiome in your gut. It's the collection of trillions of tiny microorganisms (bacteria, fungi, yeasts and viruses) living in and on our bodies, that can be likened to a kind of community or village.
These digestive-tract microbes are referred to as the gut microbiome and its role in both health and disease has been the subject of extensive research, establishing its involvement in our metabolism, nutrition, physiology, and immune function. Imbalance of the normal gut microbiota has been linked with gastrointestinal conditions such as inflammatory bowel disease (IBD) and irritable bowel syndrome (IBS), and wider systemic manifestations of disease such as obesity, type 2 diabetes, depression and allergic diseases such as rhinitis, asthma and eczema.
But did you know that a similarly complex and important ecosystem of bacteria, fungi and viruses exists in the female reproductive tract? It's known as the vaginal microbiome, and it plays a key role in keeping women healthy.
So how does it work?
For over a century it has been well documented that bacteria in the vagina maintain vaginal homeostasis, and that an imbalance or dysbiosis (a term for a microbial imbalance - think of it as if some bad influences have moved into the “community”) may be associated with poor reproductive and gynecologic health outcomes. Vaginal microbiota are of particular significance to postmenopausal women and may have a profound effect on vulvo-vaginal atrophy, vaginal dryness, sexual health and overall quality of life.
The vaginal microbiome changes in different states in a woman’s life - age, menstruation, and oestrogen levels all impact the bacterial community among other factors like smoking, sexual intercourse and hygiene. The most dramatic change is at the time of puberty when oestrogen and glycogen levels increase. This increase promotes the growth of bacteria that produce lactic acid, such as Lactobacillus species. Higher oestrogen and glycogen levels also contribute to an increased thickness of the tissue (epithelium) of the vagina and the protective mucus layer. The primary colonising bacteria of a healthy vagina is called lactobacillus. It helps to keep the environment acidic in the form of a low pH and discourage other potential pathogens like Candida spp. Gardnerella vaginalis and E.coli from thriving.
Lactobacilli form a critical line of defence against these potential pathogens through different mechanisms, such as the production of various antibacterial compounds (lactic acid, hydrogen peroxide, and bacteriocins), crowding out, and positively modulating the immune system.
Our understanding of the human genitourinary tract has greatly expanded over the last 10 years. Using high-throughput sequencing (16S rRNA) technology, the vaginal microbiota of hundreds of women have been characterised into five community states. Four of these community states are dominated by Lactobacilli species. The other community was defined as the diversity state dominated by anaerobic bacteria including Prevotella, Dialister, Atopobium, Gardnerella, Megasphaera. These five groups are called community state types (CSTs) and interestingly the predominant CST varied with race/ethnicity.
CST I is comprised predominantly of Lactobacillus crispatus. This Is considered to be the best community and least likely to develop bacterial vaginosis or acquired sexually transmitted infections
CST II: Lactobacillus gasseri
CST III: Lactobacillus iners. This is the species present in almost all women, but it appears to possess a poor ability to inhibit potential pathogens. As such it is the dominant lactobacilli in women with vaginal dusbiosi, bacterial vaginosis, HPV infections and interestingly cervical dysplasia.
CST V: Lactobacillus jenseii.
CST IV is the diversity state with lower levels of Lactobacillus and higher levels of Pe toniphilus, Prevotella, Streptococcus, Atopobium and Megasphera
As previously mentioned, the vaginal microbiome changes significantly across the female lifespan, in line with hormonal and structural features of the vaginal tissue (epithelium).
Prior to puberty, women produce little oestrogen, which results in low glycogen levels, a high microbial diversity and higher more alkaline vaginal pH. The vaginal tissue prior to puberty is thin and covered with a thin layer of mucus.
Following puberty in the pre-menopausal state when women are producing high levels of oestrogen resulting in more glycogen deposits in the epithelial cells and free glycogen is also available for Lactobacillus spp., which then predominate the healthy vaginal microbiome (CST I, II, II and V).
During the perimenopausal stage, the vaginal epithelium is thickest and covered by a thick layer of mucus.
Following menopause, the levels of oestrogen drop, decreasing glycogen and the vaginal epithelium resembles the pre-puberty stage, with less layers and a thinner mucus layer. In some cases, this leads to depletion of Lactobacillus spp. and an increase in diverse microbial species and community states -CST IV which has a higher association with vaginal symptoms that manifest as vaginal atrophy, dryness and painful intercourse.
Modified from: Muhleisen AL, Herbst-Kralovetz MM. Menopause and the vaginal microbiome. Maturitas. 2016;91:42-50.
The most common causes of vaginal microbiota dysbiosis are:
Oral or IV antibiotic use
Spermicide use
Vaginal washing / douching
Hormonal changes post-menopause
Multiple sexual partners
Increased frequency of intercourse
Smoking
Use of diaphragm
Stress
Minimising these “risk factors” then seems to be a good preventative measure, as well as considering the use of a probiotic. BUT - they must have the ability to:
Adhere to vaginal cells
Temporarily colonisation the vagina
Inhibit pathogen growth and/or attachment;
Produce lactic acid and hydrogen peroxide
Be able to survive the digestive secretion obstacles of the upper gut i.e stomach acid and bile salts.
Two strains that are commercially available to fit these criteria are:
Lactobacillus rhamnosus GR-1
Lactobacillus fermentum RC-14
Or the lovely Bio.Me Femme is a multispecies probiotic developed to work on the axis of the gut, vagina and urinary microbiomes with the aim to prevent recurrent urinary tract infections and balance these female microbiomes. The formulation consists of seven specially selected probiotic strains for their capacity to inhibit uropathogenic growth in the vagina, bladder and gut, to strengthen the intestinal barrier, and stimulate the immune system.
In health,
Tanya