The Mycobiome, the Bacterial Microbiome and Inflammatory Bowel Disease

An interesting piece of research[i] was present last week at a conference in Chicago.  Firstly, as I’ve talked about before on this blog, it’s important to remember that humans’ incredibly complex natural ecosystems have a mycobiome (native yeast population), just as we have a bacterial microbiome and should have a macrobiome, and without a doubt, each affects the other.

In this study, researchers induced colitis in mice and then infected a subset with C. tropicalis, which is a normal part of the human mycobiome.  (Apparently, it’s the second most common yeast in humans, after Candida albicans.)  The mice in this subset had markedly worse Crohn’s disease symptoms.  What makes this research even more interesting is that the mice infected with the C. tropicalis had much higher levels of proteobacteria (like types of E.coli) in their intestines – a bacteria already associated with the development of IBD.   That is, a yeast induced dysbiosis and this, in turn, caused much higher levels of proinflammatory cytokines.  They also had more severe visual signs of swelling.

“This confirmed that the presence and the abundance of fungi in the intestine have the ability to modify the bacteria living in our intestine, leading to a dysbiosis which will eventually trigger an inflammatory syndrome.”

The authors suggest that using anti-fungal medications may make a positive difference, therefore, in IBD.

What’s a really interesting thought is that we’ve known for decades that using antibiotics can lead to yeast infections.  Each keeps the other in check.  Is it not just the direct negative effect on the gut bacteria that are problematic, but also, the fact that after a round of antibiotics, yeast levels go up?  So, I got to wondering if there are any statistics on the relationship of the development of IBD to antibiotics use.  And sure enough, I found this in an article[ii] from 2013:

“We found an increased association between prior antibiotic use and an IBD diagnosis in adults just as we had in children. We found that the greater the antibiotic use, the stronger the association between antibiotic use and an IBD diagnosis.”

I also found, in this article, more than I bargained for:

“We questioned whether antibiotic use plays a role in the development of pediatric IBD. Of particular interest was whether antibiotic use in a child’s first year of life is because the gut microbiome—as far as our current understanding goes—is like a fingerprint. The gut microbiome begins to establish itself when we are young children of, maybe, 1 year or so of age. The gut microbiome is developing in that first year of life, but after this time, it stays pretty constant. Events, such as infections, may occur in that first year of life that impact the gut microbiome in such a way that some permanent changes occur….We found that children who had an IBD diagnosis were about 3 times more likely than children without an IBD diagnosis to have received antibiotics in the first year of life.”

Well, as the parent of a child given copious amounts of antibiotics starting on his 2 day of life, who then went on to develop both autism and IBD, that just made my day.

Not.

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[i] https://www.specialtypharmacytimes.com/news/intestinal-fungus-may-trigger-gut-inflammation-in-crohns-disease

[ii] Bernstein, CN. Antibiotic use and the risk of Crohn’s disease.  Gastroenterology & Hepatology. 2013; 9(6):393-395.