Our bodies, along with the rest of the planet, are overflowing with microbes, but scientists have had a hard time getting those bacteria to grow on their own in labs. But now, researchers have found that a majority of gut bacteria in the human body is actually culturable, and that could have a big impact on research in the field. Here is what lead researcher Hilary Browne of the Wellcome Trust Sanger Institute had to say about the findings, published Wednesday in Nature.
What’s the big obstacle in understanding the biology of microbes in the human body?
There have been great advances in microbiota research in recent years and we now understand a lot more about how the bacterial community within us impacts our health. However, to understand the biology behind these bacteria, we need to be able to grow them in the lab. There is a perception in the field that the majority of the microbiota are unculturable.
We used metagenomic sequencing to sequence the DNA of all the bacteria present in a fecal sample, and we then compared this to the sequence of the bacteria growing on a Petri dish that came from a fecal sample. This way, we can compare what we are growing in the lab and what we are missing. We discovered that we can actually grow the majority of the bacteria that are present in your gut.
How were you able to grow the bacteria?
As these bacteria do not survive in oxygen we grew them in anaerobic chambers and we used a publicly available growth media containing lots of different carbon sources and fatty acids that encourage the growth of a wide range of bacterial species. We were also interested in studying the bacteria in your gut that makes spores.
Spores are a form of bacterial hibernation that allow bacteria to survive adverse conditions. When conditions improve, they can germinate and continue their life cycle. All the bacteria that could not make spores died, but the spore-formers survived. We then picked individual cultures from the Petri dishes that both spore-formers and non-spore-forming bacteria were growing on and sequenced their entire genome. This allows us to understand more about the biology of these bacteria.
How can other researchers use that finding?
We have also deposited these bacteria in culture collections around the world. This will allow other researchers to acquire them and use them for their research. Using the process we have described and the bacteria we have already deposited in culture collections, other researchers can now access more of the bacteria that live in our guts. This will allow us to understand more about the biology of these bacteria, how they influence our health and hopefully will facilitate development of therapeutics to treat intestinal-associated disorders.