What does this bacterium look like?
Faecalibacterium is a rod of approximately 2 to 14 micrometers long: this is quite long for bacteria, but not that large when you know that 1,000 micrometers fit into one millimeter. Its name refers to “feces” or stool, which immediately makes the link with the gut as the preferred living environment of this bacterium.
What does science already know about this bacterium?
Faecalibacterium does not tolerate oxygen well and is therefore difficult to cultivate in the lab. Nevertheless, scientists have already discovered quite a lot about this bacterium. It is an important part of the gut microbiome, which is why research into this bacterium is so useful.
Scientists mainly focus on Faecalibacterium prausnitzii. This species was discovered in 1922 by Prausnitz, a German microbiologist, and was subsequently named after him and extensively researched. Later, other species were discovered, such as Faecalibacterium butyricigenerans and Faecalibacterium longum.
We already know that Faecalibacterium has an average genome size of approximately 3 million base pairs with 2,500 to 3,000 genes. This means that this bacterium can produce up to 3,000 different substances.
But there is more: Faecalibacterium is not only interesting for fundamental research, it is also seen as a “next-generation probiotic” or “Live Biotherapeutic Product” (LBP). What are these probiotics? Probiotics are live microorganisms that confer a health benefit on the host when administered in adequate amounts. Researchers Philippe Langella and Harry Sokol from France have shown that Faecalibacterium prausnitzii has strong anti-inflammatory properties. Low levels of this bacterium are often found in people with inflammatory bowel diseases, such as Crohn’s disease and ulcerative colitis. This insight led to the establishment of Exeliom Biosciences, a biotech company working on EXL01, an LBP based on Faecalibacterium prausnitzii. This product is currently undergoing clinical trials as a maintenance therapy for Crohn’s disease patients and is also being investigated for other conditions such as cancer and infections.
What is this bacterium doing in my gut?
Faecalibacterium is an important inhabitant of your gut and often accounts for 10% or more of the entire gut microbiome. It is a hard worker that loves food residues that you cannot digest yourself, such as fiber from fruit and vegetables. When Faecalibacterium gets to work, it converts these food residues into useful substances. Butyrate is one of the substances that Faecalibacterium is good at producing or generating. This immediately explains where the species Faecalibacterium butyricigenerans gets its name from. 😉
What is butyrate? It is a short-chain fatty acid that nourishes the intestinal wall and thus ensures a good intestinal barrier. This makes it more difficult for harmful substances to leak through the intestinal wall. Butyrate is also able to reduce inflammation. This is one way in which Faecalibacterium strengthens the immune system in your gut. But more and more substances are being discovered that this bacterium can produce to reduce inflammation, such as the recently discovered isopentenyladenine. This is yet another reason to also examine substances in stool samples in addition to bacteria, as we are doing in our VIAB2L study, in which vitamin B2 (or riboflavin) plays a central role.
Did you know that there is also a link between riboflavin and butyrate production by Faecalibacterium? Previous research has already shown that this vitamin plays an important role in the metabolism of this bacterium. Riboflavin helps to maintain the redox balance outside the cell. This allows Faecalibacterium to ferment more efficiently and produce more butyrate. In other words, sufficient riboflavin in your diet can support this bacterium in its task of producing anti-inflammatory substances. For example, riboflavin is found in animal products such as milk, eggs and meat, and in smaller quantities in green leafy vegetables. In our VIAB2L study, we also want to investigate whether we can promote these benefits by administering some extra riboflavin.
In short, having sufficient Faecalibacterium in your gut is generally very good for your gut health. It is an important target bacterium for keeping your digestion running smoothly and your immune system in balance.
Does this bacterium occur elsewhere?
Faecalibacterium feels most at home in your gut. When this bacterium moves outside its familiar environment, it cannot survive very well because it is very sensitive to oxygen. Researchers have also found this bacterium in other mammals and birds, where it also prefers to reside in the intestines.