New insight into irritable bowel syndrome and gut bacteria

New findings from the Institute of Food Research are providing insights into the interaction between bacteria and mucins, and how the specificity of these interactions affects health. The IFR researchers looked at Ruminococcus gnavus. This is a common species of gut bacteria found in over 90% of people, including infants just a few days old. It has also been implicated in gut-related health conditions. A number of studies have shown that patients suffering from Inflammatory Bowel Diseases have a disproportionate representation of R. gnavus.

This study looked at two different R. gnavus strains. Although both R. gnavus strains can use mucins, only one had the ability to survive when mucins were the sole source of food.

Comparing the genomes of the R. gnavus strains identified gene clusters used to breakdown mucins. Differences in these genes explain the different abilities of the strains to use mucins. The mucin sugar structures change in different parts of the gut and over time, suggesting the strains may be adapted for different environments or to colonise us at different times. For example, the R. gnavus strain adapted to survive solely on mucins may give it the ability to colonise the guts of newborn babies, when mucins represent the only sources of sugars for bacteria. In adults, the strains of bacteria that degrade mucins are the ones most likely to contact the cells underneath the mucus and so these strains are the ones most likely to influence health.

For further details, see the following paper:

Emmanuelle H. Crost, Louise E. Tailford, Gwenaelle Le Gall, Michel Fons, Bernard Henrissat, Nathalie Juge. Utilisation of Mucin Glycans by the Human Gut Symbiont Ruminococcus gnavus Is Strain-Dependent. PLoS ONE, 2013; 8 (10): e76341 DOI: 10.1371/journal.pone.0076341

Posted by Tim Sandle