359
With Isala, we found 359 women in whom these bacteria were dominant in their vagina. That is about 11% of all Isala participants.
What do these bacteria look like?
These are cocobacilli. The shape is something between a sphere and a rod with a not so clearly delineated cell wall. These bacteria are approximately 0.5 to 1.5 micrometres in size. And that is small if you know that 1000 micrometres fit in one millimetre.
What does science already know about these bacteria?
A little more every day. In 2019, for example, researchers at Ghent University discovered that there is not just one species of Gardnerella but different ones, such as Gardnerella vaginalis, Gardnerella leopoldii and Gardnerella swidsinskii. The name Gardnerella vaginalis clearly refers to a vaginal bacterium. Gardnerella leopoldii, on the other hand, refers to Sidney Leopold, who first described bacteria of this species. Gardnerella swidsinskii, on its turn, refers to Alexander Swidsinski, a German microbiologist who conducts extensive research into Gardnerella species and their properties.
Gardnerella vaginalis, Gardnerella swidsinskii and Gardnerella leopoldii have an average genome size between 1.5 and 1.7 million base pairs and have around 1,100 to 1,300 genes. This means that they can produce approximately 1,100 to 1,300 substances.
What are these bacteria doing in my vagina?
In the first phase of Isala, we found 359 women in whom Gardnerella bacteria were dominant in their vagina. That is approximately 11% of all participants. Based on what we knew at the time, we were unable to distinguish between the different Gardnerella species. Since Gardnerella swidsinskii and Gardnerella leopoldii were only recently discovered in 2019, not much is known about their specific characteristics yet. Research does show, for example, that Gardnerella swidsinskii regularly occurs together with Gardnerella vaginalis in the vagina. The exact role of Gardnerella swidsinskii here is not yet known, but it is something that our research team would like to study further.
We know a little more about Gardnerella vaginalis. This species can produce lactic acid, thereby lowering the acidity in the vagina. We also know that this bacterium can break down proteins in the vagina, including beneficial proteins. Some types of Gardnerella vaginalis also have venomous spikes. The biggest risk is that they can break down cells of the vaginal wall and disrupt the acidity in the vagina, making you more susceptible to infections or inflammation.
In general, there is no need to panic if Gardnerella is your dominant type. The presence of these bacteria does not always have adverse effects. For example, we already know that they are related to bifidobacteria, which have beneficial properties (read more here). Gardnerella bacteria are often found together with different types of lactobacilli. Those lactobacilli can help keep Gardnerella in check. We would also like to point out that the vaginal microbiome is somewhat dynamic. It could well be that the dominance of the Gardnerella has already disappeared.
The most important advice we can give you is to contact your doctor if you experience complaints or worry about your vaginal health. Within Isala, we even have a separate webpage with more background information, especially for doctors, so you can certainly refer to that.
Do these bacteria occur elsewhere?
Gardnerella vaginalis is most commonly found in the vagina, but this bacterium can sometimes also be found in blood or urine samples, in the pharynx or lungs, and when examining wounds or abscesses.
Gardnerella swidsinskii and Gardnerella leopoldii are relatively new species, so knowledge about their “habitats” is still quite limited. We know that they occur in the vagina. Beyond that, little is known about other places where they might thrive. Who knows, we may encounter these bacteria somewhere else in the coming years.