Mouth bacteria upsets the bowels
© Burak Karademir/Moment/Getty
Bacteria that live in your mouth could end up in the gut and trigger inflammatory bowel disease.
average person swallows around 1.5 litres of saliva every day, sending a
multitude of microbes through the body. Disturbances in gut flora, the gut’s
microbial community, are thought to cause conditions such as inflammatory bowel
disease (IBD), but tracing the source of inflammation has been difficult.
team led by researchers from Keio University fed saliva from humans with IBD to
healthy mice. After six weeks, they analysed the mice’s faeces and identified
the presence of around 20 different human oral bacteria. There was a particular
abundance of the Klebsiella — a
harmless oral inhabitant when present in healthy humans. The team injected Klebsiella into a new batch of mice and found
that it activated immune cells and triggered inflammation in the guts.
Klebsiella triggered more inflammation in mice treated
with antibiotics, suggesting that medicines that modify gut microbes could make
patients more susceptible to bowel disease.
- Science 358, 359-365 (2017). doi: 10.1126/science.aan4526