Science

Scientists identify 21 microbes that help build a healthy gut

TV Jayan : New Delhi | Updated on July 07, 2020 Published on July 07, 2020

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‘By highlighting these 21 species, we will spur research into exploring their use as probiotics, independently and in combination with other existing probiotics’

In what could be a major boon to the $50 billion dollar global probiotics industry, a team of researchers, including a scientist from the Indian Institute of Technology Madras, has identified several species of bacteria that hasten the process of rebuilding a healthy gut.

Several thousands of ‘friendly’ bacteria reside in the gut, collectively called the gut microbiome, and they contribute to many aspects of our health, from digesting food to the uptake of nutrients to beefing up immunity. These gut bacteria cells, which are in trillions, outnumber even the human cells by a factor of three or four. Their right balance is critically important for human health.

Several recent studies have shown that the loss of gut microflora diversity and their alterations are associated with various metabolic, immunological and neurological diseases, and poorer response to cancer immunotherapy. Antibiotics are known to cause profound and long-term alterations in the diversity of gut bacteria. Despite this adverse impact, indiscriminate use of antibiotics is going up significantly in healthcare and farming. There has been a 65 per cent increase in global consumption of antibiotics between 2000 and 2015.

Even though the adverse impacts of antibiotic drugs on gut microbes are long known, scientists knew very little about metabolic functions contributing to the recovery of gut microbiome.

Now, the researchers led by Niranjan Nagarajan of the Genome Institute of Singapore and Yunn-Hwen Gan of the National University of Singapore, identified 21 bacterial species associated with the recovery of gut bacteria, giving the pharma industry better insights to develop better probiotic cocktails. Contributing to this work, in the journal Nature Ecology & Evolution on Monday, is Karthik Raman, an associate professor at Bhupat and Jyoti Mehta School of Biological Sciences at IIT Madras.

Another problem associated with rampant overuse of antibiotics is increased antibiotic resistance. “The way in which this interacts with our work is the potential for incomplete recovery to serve as a risk factor for colonisation of the gut by antibiotic resistant bacteria,” said Nagarajan.

The scientists who analysed metagenome (genome of multiple organisms together) of gut bacteria of 117 people from four countries — Singapore, Canada, England and Sweden — identified 21 gut bacterial species whose synergistic working can promote the microbial abundance and diversity by nearly 100-fold after antibiotic treatment.

“What is done here is interesting. We set out to answer the hypothesis whether there are organisms that speed up the process of restoring microbial ecology to a great extent. We found that the people whose gut recover faster than others harbour such bacteria, that we call recovery-associated bacterial species (RABs),” said Raman. Interestingly, some of these bacteria are already known to scientists and are being used commonly in existing over-the-counter probiotics. More importantly, the scientists found that different species of bacteria work together in a ‘food web’ for the recovery of the gut microbiome. The collaboration with Raman’s lab was key in understanding the mechanisms through which bacteria have synergistic effects in promoting gut recovery.

“We hope that by highlighting these 21 species, we will spur research into exploring their use as probiotics, independently and in combination with other existing probiotics,” said Nagarajan, who originally hails from Chennai.

As next step, Nagarajan said, they plan to do further experiments to understand how different diets promote these 21 species in the gut, identify the mechanisms by which these species have synergistic effects and study them further in vivo to understand their potential protective functions for the host.

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Published on July 07, 2020
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