The Yeast Found In Kefir Has Been Found To Combat Disease-Causing Bacteria


If you’ve never heard of kefir, it’s actually a fermented milk product that is quite similar to yogurt. And like yogurt, it contains a ton of health benefits such as being a powerful probiotic, may protect against cancer, and has potent antibacterial properties.

Moreover, a substance created by the yeast in kefir has also been found to inhibit pathogenic bacteria, such as Vibrio cholerae and Salmonella enterica. The name of the substance is tryptophol acetate, and the way it works, is by disturbing the communication between bacteria. And what this could possibly mean is that it could aid in the development of new ways to combat antibiotic resistant bacteria.

Kefir, whose origins began in Tibet and North Caucasus, has been produced and ingested by so many people for thousands of years. And they way to make kefir can also alter, depending on the way people choose to ferment it. It’s made by infusing milk with kefir grains, creating a sour and slightly foamy drink. Kefir grains contain an interdependent group of acetic bacteria, yeasts and lactic acid bacteria.

As mentioned earlier, kefir is well-known for a number of incredible health benefits like reducing inflammation, lowering cholesterol, and giving off an antioxidant effect.

Just like probiotics, kefir is also full of antimicrobial properties. Yet scientists are still unclear as to how it actually inhibits the growth of bacteria that causes sickness and disease.

A research team from the Ben-Gurion University of the Negev (BGU) in Be’er Sheva, Israel, has discovered that there is a type of yeast in kefir that releases a certain molecule that interrupts bacterial communication called Kluyveromyces marxianus.

While scientists were already aware that the substance, called tryptophol acetate, is produced by algae and plants, it is the first time that they discovered that there is a yeast that actually makes it.

They found out that the tryptophol acetate ‘interferes with quorum sensing” – a form of microbial communication – in several disease-causing bacteria.’

When it comes to quorum sensing, what happens is the bacteria releases signaling molecules out into their surroundings. And when these molecules get up to a certain concentration, it generates revisions in gene characteristics in the bacteria of the same type of species.

With these changes, they end up allowing the disease-causing bacteria to work together in their actions, depending on how much there is. And they need that coordination in order for some of the bacteria to either safeguard themselves or assault their hosts.

In some cases, when they reach a particular bulk or mass, the microbes can actually join together and form a ‘biofilm,’ which is described as a slimy, protective coating, on the surface.


Disease-Causing Bacteria

During research in lab cultures, researchers discovered that tryptophol acetate ‘had an inhibitory effect over quorum sensing in several disease-causing bacteria,’ such as certain Gram-negative bacteria. A few of the species that they tested were as follows:

  • enterica, which is known to cause food poisoning.
  • cholerae, which from the name alone one can assess causes cholera.
  • Pseudomonas aeruginosa, which is a leading cause of pneumonia when it reaches the lungs.
  • Staphylococcus aureus, a bacteria known to trigger sepsis and other fatal infections.

Led by Ph.D. student Orit Malka, this research is found in the journal BMC Microbiome.

According to Senior author of the study, Professor Raz Jelinek, “these results are notable, since this is the first demonstration that virulence of human pathogenic bacteria can be mitigated by molecules secreted in probiotic milk products, such as yogurt or kefir.”

For the study, the scientists concentrated on the effects of tryptophol acetate on V. cholerae in particular. What they found is that the substance managed to block quorum sensing in this particular bacteria while lessening its lethality.

It managed to do this by altering the aspect of the bacterial genes that govern quorum sensing. The scientists explain that this type of disturbance or intrusion into the bacterial communication could possibly be very run-of-the-mill in such complex environments where you can find a variety of microorganisms living together, like how it does in probiotic food, or within the human gut.


Resistance to Antibiotics

As for antibiotic resistance, its development within bacteria can pose a vital and horrible threat to public health. This is why recently, scientists have been working towards finding alternatives to conventional antibiotics, like adding drugs that could intervene with quorum sensing.

The research team working on this latest discovery has actually put up a company ‘to develop and market tryptophol acetate and other small molecules’ through BGU’s technology organization, BGN Technologies.

CEO of BGN Technologies, Josh Peleg, wrote, “In a world where antibiotic resistant bacteria are becoming an imminent threat, the novel molecules discovered by BGU scientists pave a completely new path for fighting bacterial infections by disrupting cell-cell communications in pathogenic bacteria.”

Another follow-up study, which hasn’t been published just yet, explains how researchers have found that the these same molecules could possibly have anti-inflammatory properties.

Scientists share that their work in animal models of disease indicates that the molecules could possibly quiet the cytokine storm, which is described as the excessive immune response, that happens in some patients diagnosed with severe Covid-19.