Gut microbiome's role in fighting infections: Study reveals how diet can impact risk

Research reveals how gut bacteria predict susceptibility to infections like E.coli, urging increased fibre intake for protection.

A new study has found that the composition of the gut microbiome helps in predicting how likely a person will succumb to potentially life-threatening infection with Klebsiella pneumoniae, E.coli and other bugs -- and it may be altered by changing your diet.

The group of bacteria called Enterobacteriaceae, including Klebsiella pneumoniae, Shigella, E.coli and others, is present at low levels as part of a healthy human gut microbiome. However, certain catalytic factors such as increased inflammation in the body, or by eating contaminated food these bugs can cause illness and disease. In extreme cases, too much Enterobacteriaceae in the gut can be life-threatening.

How gut microbiome protect against harmful bacteria

Researchers have used computational approaches including AI to analyse the gut microbiome composition of over 12,000 people across 45 countries from their stool samples. They found that a person's microbiome 'signature' can predict whether a person's gut is likely to be colonised by Enterobacteriaceae. The results are consistent across different states of health and geographic locations.

The researchers identified 135 gut microbe species that are commonly found in the absence of Enterobacteriaceae. It likely protects against infection. The results are published in the journal Nature Microbiology. Notable among the protective gut species is a group of bacteria called Faecalibacterium, which produces beneficial compounds called short-chain fatty acids by breaking down fibre in the foods we eat.

Role of fiber in promoting gut health

This seems to protect against infection by a range of disease-causing Enterobacteriaceae bugs. The researchers suggest that eating more fibre in our diet will support the growth of good bacteria -- and crowd out the bad ones to significantly reduce the risk of illness. In contrast, taking probiotics -- which don't directly change the environment in the gut -- is less likely to affect the likelihood of Enterobacteriaceae infection.

"Our results suggest that what we eat is potentially very important in controlling the likelihood of infection with a range of bacteria, including E.coli and Klebsiella pneumoniae because this changes our gut environment to make it more hostile to invaders," said Dr Alexandre Almeida, a researcher at the University of Cambridge's Department of Veterinary Medicine and senior author of the paper.

He added: “By eating fibre in foods like vegetables, beans and whole grains, we can provide the raw material for our gut bacteria to produce short-chain fatty acids -- compounds that can protect us from these pathogenic bugs.” Klebsiella pneumonia can cause pneumonia, meningitis and other infections.