Bacterial and fungal interplay in Crohn’s disease

Published: 25-Nov-2016

Crohn's disease, an inflammatory bowel disease (IBD), is marked by inflammation of the digestive tract lining

Crohn’s disease causes intense pain, diarrhoea, weight loss, fatigue and malnutrition. The disease can affect different parts of the digestive tract, and it can be debilitating and life-threatening.

Crohn’s disease results from an aberrant immune reaction to microbial antigens in the gut.

This points to a complex relationship between genetic factors and the endogenous bacterial community (bacteriome). Research has identified species of gut bacteria that are either beneficial or harmful in Crohn’s disease. In addition to bacteria, the gut’s fungal community (mycobiome) is also gaining attention.

The makeup of one’s microbiome (which includes both the bacteriome and mycobiome) is influenced by a number of factors, including genetics, diet and environment.

As families often share genetic and environmental factors, researchers decided to look at the microbiomes of Crohn’s sufferers and their families to determine the extent to which the unique characteristics of the gut microbiome differ between those with the illness and those without.

In this 2016 study published in the journal MBio, researchers looked at nine sets of patients with Crohn’s disease and their non-diseased first-degree relatives in northern France and Belgium.

In addition, they looked at four unaffected families living in the same area. They analysed the principal component, diversity, and abundance of bacteria and fungi in the microbiome. In addition, the researchers sought to determine Crohn’s-associated inter- and intrakingdom correlations.

The results showed significant microbial interactions. Here are some of the key findings:

  • Serratia marcescens and Escherichia coli were more abundant in Crohn’s disease patients
  • In general, beneficial bacteria were decreased in Crohn’s disease patients
  • The fungus Candida tropicalis was significantly more abundant in people with Crohn’s than in those without; it was positively correlated with levels of anti-Saccharomyces cerevisiae antibodies (ASCA)
  • Abundance of C. tropicalis was positively correlated with levels of S. marcescens and E. coli.

This study suggests that interactions between bacteria and fungi may be key determinants in Crohn’s disease. The findings could help in the development of new diagnostic tools and treatments for Crohn’s disease.

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