• Reduce text

    Reduce text
  • Restore text size

    Restore text size
  • Increase the text

    Increase the text
  • Print

Microbiota, the intestinal revolution. © INRA

Microbiota, the intestinal revolution

Probiotics: bacteria that are easy to love

In 1908, the Russian scientist Ilya Metchnikov attributed the astonishing longevity of Bulgarians to the yogurt they ate. In the early 20th century, yogurt was sold exclusively in pharmacies. The idea that the bacteria in some foods contribute to health is therefore not new. In the 1960s, the concept of “probiotics” - living microorganisms that are good for us - was born. As time went on, advertisements for many products started touting the benefits of probiotics. Then the European Food Safety Authority decided to regulate the use of the word more strictly. Meanwhile, many studies have shown the benefits of lactic acid bacteria: improved intestinal transit, combatting lactose intolerance, preventing diarrhoea in newborns, and boosting the immune system. These bacteria are transitory: they are only passing through, and do not settle in like commensal bacteria in the microbiota. But a new generation of probiotics, this time from the human microbiota, are coming to the fore.

Updated on 04/27/2017
Published on 02/16/2017

. © Fotolia
© Fotolia
Probiotic medicine: a new frontier

Studies in metagenomics have brought to light a surprising fact: there is a huge difference between the intestinal microbiota of healthy people and that of people who suffer from diseases such as obesity, diabetes, and even depression. These studies have revealed the protective virtues of some commensal bacteria that are now giving way to a whole new generation of probiotics designed not to protect consumer health, but to treat illness. Ulcerative colitis and Crohn’s disease are among those illnesses that can potentially be treated by bacteria. But it is worth recalling that these budding medicine-bacteria must still prove themselves through testing as rigorous as that imposed upon new pharmaceutical drugs before they can be marketed.


. © Fotolia
© Fotolia

Yogurt and health

INRA joined forces with a team from Danone Nutricia Research to illustrate the benefits of fermented dairy products such as yogurt on the health of patients suffering from Irritable Bowel Syndrome. The intake of these products, which contain probiotics, increases populations of some bacteria that can synthesise butyrate, a fatty acid known for its beneficial effects on intestinal health. Moreover, the researchers observed that in some patients, there was a decrease in the bacteria Bilophila wadsworthia, which is suspected of contributing to the development of intestinal disorders. These two effects combined lead to improved patient health. Need another reason to pay a visit to the dairy aisle?


Bacteria to fight inflammation

C Faecalibacterium prausnitzii bacteria. © CNAM, Nadia Vasquez
Faecalibacterium prausnitzii bacteria © CNAM, Nadia Vasquez
hronic Inflammatory Bowel Disease (IBD), such as Crohn’s disease or colitis, is characterised by an inflammation of the intestinal walls. To date, there is no cure for these disorders that affect thousands of people. But new hope is dawning in INRA labs, and it goes by the name of Faecalibacterium prausnitzii, a type of commensal bacteria. It all began in 2008, when researchers noticed thatF. prausnitziiwas present in patients in remission from Crohn’s disease, but absent from those suffering a relapse. They then went about conducting experiments on model mice for the disease. The results were staggering: mice that were administered the bacteria were protected against induced colitis. Clinical testing is currently underway to develop treatment based on F. prausnitzii. Furthermore, researchers are taking a closer look at an anti-inflammatory protein produced by the bacteria, which in turn could lead to a new drug to treat IBD.

Good bacteria with altered dna

What if science could transform bacteria into harbingers of health? This is precisely what one INRA team is trying to do, in the fight against Crohn’s disease. The idea is simple: take lactic acid bacteria and incorporate genes into their DNA that produce protein that is beneficial to health. The bacteria could then deliver the protein to the gastro-intestinal tract as it goes about its business. Initial testing is cause for hope: thanks to these enhanced bacteria, researchers were successful in curing model mice of Crohn’s disease.

Probiotics and prebiotics: not to be confused

As similar as the two words may sound, they designate two very different things. Probiotics are bacteria which, when ingested live, have a beneficial effect on health. Prebiotics*, on the other hand, are oligosaccharides that bacteria of the microbiota feed upon. And each type of bacteria has its own tastes and needs. Thanks to prebiotics, it is possible to target good bacteria, and specifically promote their growth to reap benefits such as increased mineral absorption and improved immune response.

Probiotics and bovine mastitis: a path worth exploring

Mastitis is a scourge for ruminants and their owners. This inflammation of the mammary glands is caused by pathogens such as Staphylococcus aureus.Treatment comes at a high cost for the dairy industry, not to mention the toll the disease takes on milk production. To date, no viable vaccine is available. When infection strikes, breeders must turn to antibiotics, which come with no guarantee. An INRA team is developing probiotics generated from lactic acid bacteria present in the microbiota of cow teats (extremity of the udder). The preliminary results are promising:in vitroexperiments have shown that one of the bacteria, Lactobacillus casei, reduced the capacity of staphylococcus to adhere to mammary epithelial cells. But that’s not all: when lactobacilli are present, the pathogen is less apt to invade cells. Indeed, when it does get into cells, the staphylococcus sidesteps the animal’s immune system, and does little to combat mastitis. As a next step, scientists will test the efficiency of Lactobacillus caseiin dairy cows.