Fungus key factor in Crohn's disease: study

Washington, Researchers have for the first time identified a fungus as a key factor in the development of Crohn's disease - a groundbreaking finding that may lead to potential new treatments for the debilitating inflammatory bowel disease.

The researchers led by Case Western Reserve University School of Medicine in the US also linked a new bacterium to the previous bacteria associated with Crohn's.

"We already know that bacteria, in addition to genetic and dietary factors, play a major role in causing Crohn's disease," said the study's senior author, Mahmoud A Ghannoum, from Case Western Reserve and University Hospitals Cleveland Medical Centre.

"Essentially, patients with Crohn's have abnormal immune responses to these bacteria, which inhabit the intestines of
all people," said Ghannoum.

"While most researchers focus their investigations on these bacteria, few have examined the role of fungi, which are also present in everyone's intestines," he said.

The groundbreaking findings could lead to potential new treatments and ultimately, cures for the debilitating inflammatory bowel disease, which causes severe abdominal pain, diarrhea, weight loss and fatigue, researchers said.

"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," said Ghannoum.

The fungal community that inhabits our body is known as the mycobiome, while the bacteria are called the bacteriome. 

The researchers assessed the mycobiome and bacteriome of patients with Crohn's disease and their Crohn's-free first
degree relatives in nine families in northern France and Belgium, and in Crohn's-free individuals from four families
living in the same geographic area.

They analysed feacal samples of 20 Crohn's and 28 Crohn's-free patients from nine families and of 21 Crohn's-free patients of four families.

The researchers found strong fungal-bacterial interactions in those with Crohn's disease: two bacteria (Escherichia coli and Serratia marcescens) and one fungus (Candida tropicalis) moved in lock step.

The presence of all three in the sick family members was significantly higher compared to their healthy relatives, suggesting the bacteria and fungus interact in the intestines. 

Test-tube research by the team found that the three work together to produce a biofilm - a thin, slimy layer of microorganisms found in the body that adheres to, among other sites, a portion of the intestines - which can prompt inflammation that results in the symptoms of Crohn's disease.

This is first time any fungus has been linked to Crohn's in humans; previously it was only found in mice with the
disease, researchers said. 

The researchers also found that the presence of beneficial bacteria was significantly lower in the Crohn's patients, corroborating previous research findings. 

The finding was published in the journal mBio.