By analyzing the viral component of the intestinal microbiota, the researchers discovered more than 33,000 different viral populations. This makes the composition of the microbiota of each individual unique.
- Analysis of the virobiota of nearly 2,000 Western subjects has identified more than 33,000 unique viral populations.
- There is no central group of intestinal viruses common to all humans: they adapt to our diet and our environment.
- A highly diverse virome contributes to good health, indicating that viruses in our guts could be a new treatment, especially for superbugs.
It’s not just our fingerprints or our DNA that are unique: so is our virobiota, that is to say the viral component of the intestinal microbiota. This is the discovery made by researchers at the Ohio State University (United States). In their study, aimed at building a comprehensive database viral populations in the human digestive systemand published in the journal Cell Host & Microbe, researchers analyzed viruses from the gut of 1,986 healthy and sick people in 16 Western countries. They were thus able to identify 33,242 unique viral populations, the majority of which are completely harmless.
“We have established a solid starting point to see what the virome looks like in humanssays Olivier Zablocki, postdoctoral researcher in microbiology and co-author of the study. If we can characterize the viruses that keep us healthy, we could use this information to design future therapies for pathogens that cannot be treated with drugs.”
A viral signature specific to each individual
Based on a careful analysis of 32 studies of gut viruses conducted over a decade, the researchers found that although a few viral populations are shared among a subset of people, there is no There is no core group of intestinal viruses common to all humans.
Their work is all the more colossal, as viruses, unlike bacteria, are difficult to detect because their genomes do not contain a sequence of common signature genes. “We used machine learning on known viruses to help us identify unknown viruses, explains Ann Gregory, first author of the work. We were interested in how many types of viruses we could see in the gut, and we determined by how many types of genomes we could see since we couldn’t see viruses visually.”
Viruses to fight multi-resistant bacteria
While there is no common group of viruses, the researchers have nevertheless highlighted some trends. Thus, in healthy Western individuals, age influences the diversity of viruses in the gut, which increases dramatically from childhood to adulthood and then decreases after age 65.
People living in non-Western countries have a greater diversity of intestinal viruses than Westerners. This suggests that diet and environment drive the virome differences.
“A general rule in ecology is that greater diversity leads to a healthier ecosystemrecalls Ann Gregory. We know that a greater diversity of viruses and microbes is generally associated with a healthier individual. And we saw that healthy individuals tend to have a greater diversity of viruses, which indicates that these viruses can potentially do something positive and have a beneficial role.”
For researchers, this discovery gives hope that viruses may soon represent a new class of drugs to fight pathogenic bacteriaand in particular those who have developed antibiotic resistance. Better knowledge of viruses in the gut environment could also improve understanding of the gastrointestinal symptoms experienced by some of the sickest patients with Covid-19. “They could also serve as the basis for something we could deploy in the world’s oceans to fight climate change.”Advance Matthew Sullivan, professor of microbiology and co-author of the study.
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