Dr Trevor Lawley and Professor Gordon Dougan are bug hunters, albeit not the conventional kind. The bugs they collect are invisible to the naked eye. And even though we’re teeming with them, researchers are only beginning to discover how they keep us healthy – and how we could use these bugs as drugs.
Both researchers lead groups at the Wellcome Trust Sanger Institute where they investigate the secrets of the micorbiome and how it contributes to our health. “We’re coated with microorganisms – bacteria, viruses, fungi – they outnumber human cells by at least three to one, so we’re more microbial than eukaryotic,” Lawley explains. The average human intestine harbours some 100 trillion bacteria from 1,000 species. They have around three million genes and make up 3% of our body weight.
The idea that our microbiome contributes to our health is not new. In 1908, the Russian microbiologist Ilya Mechnikov won a Nobel Prize for his discovery of phagocytes. He also sought to nurture his microbiota by consuming copious quantities of fermented milk, having noticed the longevity of yoghurt-loving Bulgarians.
Since then, the microbiome has been implicated in many areas of health and disease. “Evidence is accumulating that our microbiota can protect us against infection and inflammatory diseases of the bowel, influence factors such as obesity, and that bad microbiota, such as Clostridium difficile, can damage us,” Dougan explains. C. diff is a key part of this story. First described in the 1930s, C. diff lives in the gut of around 3% of healthy adults and, kept in check by a healthy microbiota, it does no damage. When antibiotics disrupt the microbiota, however, C. diff can be life threatening, especially among frail, elderly adults in hospitals and care homes. In such circumstances what works best is not more antibiotics, but reintroducing gut bugs from healthy volunteers via faecal transplants. While not the most marketable of treatments, its astonishing success led Lawley and Dougan to believe that the microbiome could be an important therapeutic target.
“We’re collecting samples of poo from around the world – from Vietnam and India to Nigeria and Kenya – to build a globally representative collection of microbiome bacteria. No-one else has such a large and diverse collection,” Dougan says. “It will allow us to mine these isolates – and their genomes – for new antibiotics and design new bacterial-based therapies.”
Read the full article for more details.