Vaginal microbiome: what grows down below

Grab your lab coat and safety goggles because we’re about to get geeky.

So, the word microbiome seems to have become a serious wellness buzzword these days. And arguably the human microbiome, which is a term used to refer to the bacterial population that resides in the body, is one of the most exciting areas of science and medicine to be discovered this century. It’s taken us a pretty long time to realise that not all bacteria actually cause disease, and in fact some actually help us to maintain a state of health and wellbeing.

In 1892 a German gynaecologist called Albert Döderlein identified bacteria in the human vagina, and of course, he named them after himself ‘Döderlein’s bacilli’. Some reports say he was the first person to introduce the use of rubber gloves in obstetrics and gynaecology too, so I think I’ll let him have that one, because I don’t fancy going barehanded at work and I’m pretty sure none of my patients would be that keen either. So it turns out this clever chap was describing Lactobacillus, which is the most common type of bacteria in the human vagina. Then everyone sort of lost interest in vaginal bacteria until the use of DNA sequencing helped us to discover what other things are growing down there.

The vaginal microbiome (but let's use the term VM for short...cos some of you are still wincing every time I write the word ‘V-A-G-I-N-A’) is pretty simple compared to that of most other areas of the body including the gut, skin, nasal passages etc. And by that I mean it contains far fewer varieties of bacteria; usually from one-five different species, although up to 25 in a small proportion of women, which is far less than the gut, with about 200. Lactobacillus species are the most frequently found in the vagina, Lactobacillus crispatus and Lactobacillus iners being the most common. In some women, however, there are no Lactobacillus to be found, resulting in an overgrowth of a huge variety of other bugs including Streptococcus, Atopobium, Gardnerella, Prevotella to name but a few. We don’t generally associate these bad boys with health, and these can cause a disorder known as bacterial vaginosis, which is associated with nasty smelling discharge and irritation and is pretty darn unpleasant for anyone that has it, although is not truly a sexually transmitted disease as lots of people think.

 The vaginal microbiome structure as first classified by Ravel et al. Proc Nat Acad Sci 2011. Is it science or is it modern art?

The vaginal microbiome structure as first classified by Ravel et al. Proc Nat Acad Sci 2011. Is it science or is it modern art?

Now whilst the VM may be simple, it most certainly is not stupid…it’s pretty damn clever. Let’s think of the vagina as the entrance to a beautiful temple, and the Lactobacillus bacteria are the monks who protect it. These monks work day and night to keep the temple safe by stopping the growth of the ‘bad boys’ I mentioned above, and other heinous creatures including HPV and even HIV infections, and most importantly they produce lactic acid which again stops growth of the baddies, and also helps to keep everything clean by gently sloughing off the dead cells in the vagina (much like that acid face wash/toner/mask you just used on your face). The also keep the peace by preventing inflammation at bay by talking to the immune system and telling them that everything is all cool.

Ok, so these monks are a bit ‘out there’ since they’re willing to launch an acid attack, but that’s as violent as they get, and if they’re attacked, they tend to get afraid and run…in particular they don’t like douching because they don’t cling on to the vaginal walls very well and hence they get washed away and then bad bacteria start to grow and run amok causing inflammation and increase the risk of getting a sexually transmitted infection, cervical cancer, premature labour, failed attempts at IVF and are probably also associated with miscarriage too. Lactobacillus also hate smoking, but that’s a tale for another day.

There’s still so much to be learned about the VM, because it doesn’t seem to be a ‘one-size-fits-all’ kind of situation. Some women are completely healthy in the absence of these awesome Lactobacillus guys, whereas others have various complications as listed above. We’re also starting to realise that not all of the different types of Lactobacillus are equal in the health stakes because some species might actually be more protective than others. If we can work out which bacteria really are the most healthy and exactly how the dynamics of this community works to protect us from disease, then it would be possible to use pre- and probiotics to keep the VM healthy and prevent disease. So the VM has potentially massive implications for female and reproductive health and there’s going to be a lot of exciting research coming out over the next few years, which I look forward to sharing with you. The VM would definitely be my specialist subject on Mastermind!

I’ll write another post about how you can try and keep your VM in tip top condition soon. But for now if you’re feeling super geeky, then I’m leaving a link to the second half of the podcast I recorded with Laura Thomas about the VM, where we talk a little bit more about the scientific stuff.

Over and out,

Dr Anita


Go follow Laura @laurathomasphd and check out her website