Human Microbiome Snapshot

Alice McCarthy, December 9th, 2011
  • Fusobacterium have been found in unexpectedly high levels in a
    study of colorectal cancer.
    Photo credit: By MarcoTolo at en.wikipedia [Public domain],
    from Wikimedia Commons

The human microbiome is the community of organisms that live, either peacefully or in mortal combat, inside of our bodies or on our skin. Broad researchers and affiliate scientists have been studying the human microbiome with the goal of learning how it influences health or disease. A few of this year’s highlights:

Inflammatory Bowel Disease - A precise pathogen has never been identified in IBD. But Broadies Dirk Gevers and Doyle Ward teamed with colleagues to recently discover that the microbial environment in patients with pouchitis (inflammation of the ileal pouch) associated with ulcerative colitis (UC) is different from healthy pouches in people with UC. Specifically, those with pouchitis had more Firmicutes and Verrucomicrobia but lower counts of ‘healthy’ Bacteroidetes and Proteobacteria.

Colon cancer – Broad senior associate member Matthew Meyerson and his colleagues recently reported finding unusually high levels of the bacteria Fusobacterium in a study of colorectal cancer tumors. Though a causal role has not been proven – the higher bacteria counts may just grow exceptionally well in the tumor microenvironment – they continue to look for any associations between potential microbiome pathogens and cancer.

Gene Swap– A study published last month by Broad associate member Eric Alm and his lab reveals that bacteria within our bodies rapidly swap and gain genetic information and that this exchange is uniquely tied to the ecosystem of the human microbiome. You can find out how our bacteria “retweet” things like antibiotic resistance in a blog entry here.

Immune System Interactions – Dirk Gevers and colleagues are finding that bacteria adapt to the human intestinal environment – with good results or poor – by influencing the immune system in previously unknown ways.

In the coming year, Broad researchers and a variety of others working in the field will be finding out more about the human microbiome as some of the first large-scale results from the NIH-funded Human Microbiome Project are expected. The project is a study of the microbial community found in 18 body sites of 300 healthy people. Get ready to find out more about who’s in there and what they’re up to.