Nearly 2,000 unknown bacterial species found in the human gut

A team of scientists from the European Molecular Biology Laboratory – European Bioinformatics Institute and the Wellcome Sanger Institute have identified 2,000 previously undocumented bacteria within the human gut. This new discovery proves that, although scientists are getting closer to listing all commonly-found microbes in the North American and European human gut, there is a lack of data from other regions in the world.

Their findings, published February 11th in Nature, were achieved by using computational methods, which helped scientists reconstruct the genomes of these mystery bacteria.

“Computational methods allow us to understand bacteria that we cannot yet culture in the lab,” said Rob Finn, an EMBL-EBI Group Leader. “Using metagenomics to reconstruct bacterial genomes is a bit like reconstructing hundreds of puzzles after mixing all the pieces together, without knowing what the final image is meant to look like, and after completely removing a few pieces from the mix just to make it that bit harder.”

“Researchers are now at a stage where they can use a range of computational tools to complement and sometimes guide lab work, in order to uncover new insights into the human gut,” he explained.

It is believed that these 2,000 gut microbes have remain hidden for so long due to the fact that they are low in abundance and/or cannot survive outside of the gut. However, these microbes and others may or may not present themselves in human guts from outside Europe and the United States.

“We are seeing a lot of the same bacterial species crop up in the data from European and North American populations,” Finn said. “However, the few South American and African datasets we had access to for this study revealed significant diversity not present in the former populations. This suggests that collecting data from underrepresented populations is essential if we want to achieve a truly comprehensive picture of the composition of the human gut.”

The computational methods use allow researchers to estimate how many bacterial species are in the human gut and what role they may play within the gut as a whole, as Postdoctoral Fellow at EMBL-EBI and the Wellcome Sanger Institute Alexandre Almeida said.

“In this study, we leveraged the most comprehensive public databases of gastrointestinal bacteria to identify bacterial species that have not been seen before,” Almeida added. “The analysis methods we used are highly reproducible and can be applied to larger, more diverse datasets in the future, enabling further discovery.”

“Research such as this is helping us create a so-called blueprint of the human gut, which in the future could help us understand human health and disease better and could even guide diagnosis and treatment of gastrointestinal diseases,” Trevor Lawley, Group Leader at the Wellcome Sanger Institute, concluded.

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By Olivia Harvey, Earth.com Staff Writer

Image Credit: Spencer Phillips/EMBL-EBI