🦠 Healthy people host these previously unknown bacteria

Our gut houses a vast community of bacteria, a large number of which remain to be identified. Recently, an observation caught the attention of scientists: a specific group of bacteria, named CAG-170, is consistently found in greater quantities in healthy people around the world. This presence raises a question: could these microorganisms be invisible protectors of our body?

A research team from the University of Cambridge analyzed the gut microbiomes of over 11,000 individuals from 39 countries. To do this, they used cutting-edge computational methods to track the genetic signature of the CAG-170 group. The work established that levels of these bacteria were higher in people not suffering from chronic diseases, such as inflammatory bowel disorders or obesity.


This discovery is based on a technique called metagenomics. The scientists assembled a catalog of microbial genomes, dubbed the 'Unified Human Gastrointestinal Genome catalog,' which aggregates genetic data from the entire gut microbiome. This initiative made it possible to catalog more than 4,600 bacterial species, many of which were previously unrecorded, and to provide genetic fingerprints to detect them.

By scrutinizing the genes of CAG-170, the team observed that this group can generate significant amounts of vitamin B12 and possesses enzymes capable of breaking down various carbohydrates, sugars, and dietary fibers. The production of vitamin B12 seems to benefit other beneficial bacteria in the gut, thereby developing the entire digestive ecosystem.

The analyses corroborated the link with health. In a study involving over 6,000 healthy people, CAG-170 stood out as the group most associated with a stable microbiome. Furthermore, reduced amounts of these bacteria were linked to an intestinal imbalance, or dysbiosis, often observed in conditions such as irritable bowel syndrome or depression.

These results open avenues for future therapies. Currently, the probiotic industry often uses the same species for decades. The discovery of CAG-170 could enable the development of more precise probiotics, designed to restore microbiome balance and improve gut health.

Dr. Alexandre Almeida, lead author of the study published in Cell Host & Microbe, indicates that these bacteria are part of the 'hidden microbiome' and appear to play a fundamental role by participating in food digestion and maintaining intestinal harmony.

Next-generation probiotics

Probiotics are living microorganisms consumed for their positive effects on health, particularly for balancing gut flora. Usually, they rely on a limited number of bacterial species, such as lactobacilli or bifidobacteria, which have been studied and cultivated for a long time.

Nevertheless, with advances in microbiome research, it is clear that many beneficial bacteria, such as CAG-170, are not part of current probiotics. These advances suggest that the sector could progress towards more targeted formulations, integrating newly characterized species for more specific actions.

Developing such probiotics involves overcoming certain obstacles, such as culturing recalcitrant bacteria in the laboratory. Innovative processes, for example co-culture or genetic engineering, could facilitate the large-scale production of these microorganisms.

Ultimately, these next-generation probiotics could be tailored to each individual's microbiome profile, thus offering more effective interventions to prevent or manage digestive disorders and other conditions related to intestinal imbalance.