A team of microbiologists has isolated 105 completely new species of bacteria from healthy people’s intestines.
Forster et al created the most comprehensive collection of human intestinal bacteria to date.
About 2% of a person’s body weight is due to bacteria and the intestinal microbiome is a major bacterial site and an essential contributor to human health.
Imbalances in our gut microbiome can contribute to diseases and complex conditions such as inflammatory bowel disease, irritable bowel syndrome, allergies and obesity.
However, as many species of gut bacteria are extremely difficult to grow in the lab, there is a huge gap in our knowledge of them.
To assemble a comprehensive collection of bacterial isolates from the human gastrointestinal tract, Dr. Samuel Forster of the Wellcome Sanger Institute and Hudson Institute of Medical Research and his colleagues studied fecal samples from 20 adults from the UK and Canada.
They successfully grew and DNA sequenced 737 individual bacterial strains from the samples.
Analysis of these isolates revealed 273 separate bacterial species, including 173 that had never previously been sequenced.
This collection represents 31 families in the phyla Actinobacteria (53 genomes, 16 species), Bacteroidetes (143 genomes, 40 species), Firmicutes (496 genomes, 203 species) and Proteobacteria (45 genomes, 14 species).
Of these, 105 species had never even been isolated before.
“This study has led to the creation of the largest and most comprehensive public database of human health-associated intestinal bacteria,” Dr. Forster said.
“The gut microbiome plays a major in health and disease. This important resource will fundamentally change the way researchers study the microbiome.”
The new culture collection and reference genomes will make it much cheaper and easier for researchers to determine which bacteria are present within communities of people and research their role in disease.
“For researchers trying to find out which species of bacteria are present in a person’s microbiome, the database of reference genomes from pure isolates of gut bacteria is crucial,” said study co-author Dr. Rob Finn, a scientist at EMBL’s European Bioinformatics Institute.
“Then if they want to test a hypothesis, for example that a particular species is enriched in a certain disease, they can get the isolate itself from the collection and physically test in the laboratory if this species seems to be important.”
“This culture collection of individual bacteria will be a game-changer for basic and translational microbiome research,” said study senior co-author Dr. Trevor Lawley, a researcher at the Wellcome Sanger Institute.
The findings appear in the journal Nature Biotechnology.
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Samuel C. Forster et al. 2019. A human gut bacterial genome and culture collection for improved metagenomic analyses. Nature Biotechnology 37: 186-192; doi: 10.1038/s41587-018-0009-7
