Fungus Plays Key Role in Development of Crohns Disease

For the first time, researchers have identified the presence of fungi in the intestines that are a key factor in the disease.

Groundbreaking research has identified a fungus that plays a key role in the development of Crohn’s disease.

It has been previously found that in addition to genetic and dietary factors, bacteria plays a major role in causing Crohn’s disease. A study published in mBio noted that targeting bacteria could lead to new treatments and potentially a cure for Crohn’s disease.

Fungi and bacteria differ in that fungi are eukaryotes and are closer to humans than bacteria, which are prokaryotes. Both fungi and bacteria are present throughout the body, and researchers in the current study previously found that people have between 9 and 23 fungal species in their mouths.

“Essentially, patients with Crohn’s have abnormal immune responses to these bacteria, which inhabit the intestines of all people,” said senior and corresponding study author Mahmoud A Ghannoum, PhD. “While most researchers focus their investigations on these bacteria, few have examined the role of fungi, which are also present in everyone’s intestines.

“Our study adds significant new information to understanding why some people develop Crohn’s disease. Equally important, it can result in a new generation of treatments, including medications and probiotics, which hold the potential for making qualitative and quantitative differences in the lives of people suffering from Crohn’s.”

For the study, researchers assessed the mycobiome (fungal community) and bacteriome (bacteria community) of Crohn’s disease patients, as well as their Crohn’s-free first degree relatives in 9 families in northern France and Belgium, and in Crohn’s-free individuals from 4 families living in the same area. The fecal samples of 20 Crohn’s disease patients and 28 Crohn’s-free patients from 9 families were analyzed, as well as the samples from 21 Crohn’s-free patients of 4 families.

The results of the analysis revealed there were strong fungal-bacterial interactions in the samples of the Crohn’s disease patients. Two bacteria called Escherichia coli and Serratia marcescens, as well as 1 fungus called Candida tropicalis moved in lock step, according to the study.

The presence of all 3 were found to be significantly higher in the sick family members compared with their healthy relatives. This suggests that the fungus and bacteria interact in the intestines.

Additional findings from the teams test tube research showed that the 3 worked together to produce a biofilm, which can promote inflammation that results in Crohn’s disease symptoms. The 3 worked together by the E. coli cells fusing to the fungal cells, and the S. marcescens forming a bridge to connect the microbes.

In the current study, there were several firsts. These findings showed a link between any fungus and Crohn’s disease in humans, which previously was only found in mice. The study also was the first to included S. marcescens in the Crohn’s-linked bacteriome.

Findings that the presence of beneficial bacteria was significantly lower in the patients with Crohn’s, which further corroborates previous research.

“Among hundreds of bacterial and fungal species inhabiting the intestines, it is telling that the 3 we identified were so highly correlated in Crohn’s patients,” Ghannoum said. “Furthermore, we found strong similarities in what may be called the ‘gut profiles’ of the Crohn’s-affected families, which were strikingly different from the Crohn’s-free families. We have to be careful, though, and not solely attribute Crohn’s disease to the bacterial and fungal makeups of our intestines. For example, we know that family members also share diet and environment to significant degrees. Further research is needed to be even more specific in identifying precipitators and contributors of Crohn’s.”