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For mice, swapping fecal bacteria can mean life or death

burgers.jpgPosted on behalf of Nicola Jones

Imagine a world where ‘eat shit’ isn’t an insult, but way to save your life. Pathogen microbiologist Brett Finlay of the University of British Columbia has shown that, in mice, resistance to a deadly e. coli-like bacterium depends on their gut microbes – and that those microbes can be swapped around by effectively feeding the mice each others’ feces.

Finlay looked at a mouse model of e. coli 0157, a bug that often contaminates hamburger meat. In mice, the equivalent bug is called Citrobacter rodentium. One strain of mice (called NIH Swiss) is known to be resistant to this pathogen. Another (C3H/HeJ) is known to quickly fall victim to the bug – all will die within a couple of weeks of exposure. Finlay wiped out the normal gut bacteria of someC3H/HeJ mice with antibiotics, and then fed them a dose of treated NIH Swiss feces to repopulate their guts (through a technique called ‘oral lavage’, involving a feeding tube). This upped their survival rate from 0 to nearly 80%, he told the International Human Microbiome Congress in Vancouver, Canada, on Thursday. Feeding NIH Swiss mice with C3H/HeJ microbes similarly caused their downfall.

“When 100 people at a wedding eat the potato salad, only a few get sick,” says Finlay. He thinks these as-yet-unpublished results might help to explain why. “Resistance to many diseases could be from our microbiota,” he extrapolates. The results aren’t surprising, says Finlay, but nail down proof for an effect that most microbiologists assumed could happen.

Fecal transplants are already done for some people with serious colon infections; feces are taken from someone, usually a relative, and introduced rectally into the patient. But experiments like Smith’s and Finlay’s could help to point the way towards clinical applications (including preventative measures) for less serious conditions, with less invasive treatments – perhaps with a pill.

Francis Ouelette, a bioinformatician at the Ontario Institute for Cancer Research who is an external advisor for the US Human Microbiome Project, one of the big, over-arching bodies in this field, says that Finlay’s work is impressive, and that mouse models like these are the future of the field. “The kinds of thing that Brett does is definitely the way to go,” he says. Jeff Gordon’s lab at Washington University in Saint Louis, Missouri, is doing similar work, creating ‘humanized’ mice to study how microbes affect us (see Do gut bacteria worsen malnourishment?).

Image: Centres for Disease Control and Prevention


  1. Report this comment

    Scott Kight said:

    I thought this was fascinating and was surprised to learn that fecal transfusion has been used to treat colitis in humans.

    Certainly the idea would seem more palatable (pun intended) if it were administered in the form of a refined pill!

    Thanks for the news. I wrote about your post in my own blog:

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    Gillian Kennedy said:

    My sister-in-law, from B.C., had a fecal transfusionin 2008 from her sister. She was unable to have this procedure in British Columbia and had to travel to Calgary, Alberta. Since then, she has had no further problem from a C.difficile nocosomial infection that had been treated unsuccessfully with antibiotics for almost 2 years.

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    trudy Strasser said:

    As a Lab tech doing microbiology I use to test stools for pathogens. Most gut flora were gram negative coliforms. Most probiotics on the market are Gram positive lactobacillus or bifidus. why do we not use healthy coliforms probiotics such as used in Germany called mutaflora?

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    Melody Lewis said:

    Interesting point Trudy. What is it about GNR’s that have kept them off the market in the U.S.? Is it the fear of pathogens?

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