Vaginal flora

The vaginal microbiome changes constantly throughout a woman’s life - from birth through puberty and reproductive age to menopause. The exact composition depends not only on a woman’s hormonal status, but also on her ethnicity and lifestyle, including her dietary habits and hygiene and sexual practices.

In the vaginal area, lactic acid bacteria (Lactobacillus spp., LAB) dominate in Caucasian women of childbearing age. The female sex hormone estrogen controls the concentration of lactobacilli, which are also called Döderlein bacteria after the German gynaecologist Albert Döderlein (1860 to 1941). The group includes over 170 different species of differently sized, unflagellated, gram-positive rods. They produce lactic acid, and some also produce hydrogen peroxide, which has a disinfecting effect. Examples of lactobacilli of the vaginal flora are L. crispatus, L. gasseri, L. jensenii and L. iners.

If the vaginal flora is in balance, this protects the woman against various infectious, urogenital and metabolic diseases. However, hormonal influences, stress, smoking, changing sexual partners, medication, chronic metabolic diseases and improper intimate care can change the composition of the vaginal microbiome. Bacterial vaginosis is when the number of lactobacilli in the vagina decreases and pathogenic bacteria spread.

Probiotics can rebalance the vaginal microbiome. Supplements (such as Omni Biotic Flora plus+, Vagisan Biotin-Lacto) contain various beneficial strains of bacteria to colonise the vagina from the intestine. Lactobacilli excreted with bowel movements reach the vaginal mucosa via the perineum for this purpose. Medicines for vaginal use may also contain lactic acid bacteria (such as Vagisan ProbioFlora Lactic Acid Bacteria, Döderlein Vaginal Capsules) or directly supply the lactic acid that is important for optimal pH (such as Vagiflor Vaginal Suppositories, Lactofem Lactic Acid Vaginal Suppositories, or KadeFungin Lactic Acid Cure). In studies, the intravaginal application of lactic acid bacteria was able to prevent a renewed vaginal infection.

For women with bacterial vaginosis who react to antibiotics with severe side effects or for whom they are contraindicated, a therapy with probiotics can be tried as an alternative. However, the treatment of vaginosis with probiotics instead of antibiotics has been studied less well.

Some studies have tested probiotics in combination with antibiotics to treat a vaginal infection. In 2014, a group of researchers from China published the results of a meta-analysis that included twelve randomised controlled trials with 1304 patients. It showed that probiotic supplementation could significantly improve the cure rate of bacterial vaginosis. However, the evidence for the positive effect was limited due to limitations such as the heterogeneity of the study designs, according to the authors.

Another approach is to transfer the entire microbiome of a healthy donor instead of individual bacteria. That a microbiome transfer can work in principle has already been shown with stool transplants for intestinal infections such as therapy-refractory Clostridium difficile-associated diarrhoea (CDAD). Vaginal microbiome transplantation (VMT) could help analogously patients suffering from symptomatic, recurrent bacterial vaginosis. In a first exploratory study, five women were treated with VMT.

In four of them, VMT led to complete long-term remission by the end of the follow-up period. No side effects were observed in any of the five participants. However, remission required repeat VMT in three patients, including a donor switch in one case.

Another approach to bring the vaginal flora back into balance is to take prebiotics. These are indigestible food components that are supposed to promote the growth of beneficial bacteria such as lactobacilli. Examples include dietary fibres such as inulin and oligofructose. However, sufficient evidence that prebiotics are effective is lacking. The same applies to the numerous home remedies from tea tree oil to yoghurt to vinegar water. In the worst case, they can actually do harm instead of good.

Patients who want to take probiotics to prevent a recurrence of vaginal infections should be prepared for the fact that it can take weeks to months until the colonisation is back in balance. The pharmacy team can advise affected women that the way they care for their intimate parts can also help prevent vaginal infections or their recurrence. Lukewarm water is usually enough to clean the vaginal area.