Lactobacillus iners


With Isala, we found 903 women in whom this bacterium was dominant in their vagina. That is about 28% of all participants. 

Lactobacillus iners

What does this bacterium look like? 

Lactobacillus iners is a short rod, sometimes almost a ball with a slightly thinner wall than the average Lactobacillus. This bacterium is sometimes smaller than 1 micrometre, which is very small when you recall that 1000 micrometres fit into one millimetre. The name refers to the word iners, lazy. But actually, this bacterium is not really lazy; it is just very difficult to grow in a lab. This bacterium feels completely at home in your vagina! 


What does science already know about this bacterium?

Because this bacterium is so tiny and difficult to grow in a lab, Lactobacillus iners was only discovered in 1999. So, we don’t know much about this type of Lactobacillus yet. Although we are facing a breakthrough because – after many attempts- we have recently grown our first Lactobacillus iners in our own Isala lab! 

We already know that this bacterium has a smaller genome of about 1.3 million base pairs with more than 1400 genes. This means that this bacterium can produce about 1,400 different proteins. That’s less than the average Lactobacillus, but that’s because she feels completely at home in the female vagina. This bacterium is less adapted to survive in conditions outside the vagina. 

Komt ze nog ergens anders voor?

What is this bacterium doing in my vagina? 

Like any type of Lactobacillus, this bacterium produces lactic acid and thus ensures a low acidity in the vagina. But it can also make many other valuable molecules. In this way, the Lactobacillus iners protects your vagina against infections or pathogenic bacteria or fungi. Unravelling those molecules is something that Isala’s team is happy to work on in the future. 

We will also further investigate the fluctuations in the presence of Lactobacillus iners. After all, we suspect that the composition of your vaginal microbiome fluctuates during your cycle. The hypothesis is that Lactobacillus iners is more common just after your period. Blood contains many nutrients on which this bacterium can grow well. Lactobacillus iners has also an excellent immune system for so-called bacteriophages, which are viruses that can make (healthy) bacteria sick. We suspect that it is precisely this property that ensures that this bacterium can remain stable during your period. 

What is this bacterium doing on my skin?

Lactobacillus iners have been found in low concentrations on the skin and in the nose in previous research. At Isala, we found them most frequently in the groin area, but we can find these Lactobacillus iners in many different places on the skin. For example, in previous research we also found Lactobacillus iners in the elbow cavity of children and adults.

Waar komen ze nog voor?

Does this bacterium occur elsewhere?

We have already found it in previous research on the skin and in the nose, but in much lower numbers than in the vagina. This may be because this bacterium is difficult to see through the microscope and not easy to grow in the lab. So maybe we’ll see this bacterium elsewhere in the coming years.