Don’t Poo-Poo Stool Transplants!

October 19, 2008 at 6:27 pm

From yesterday’s StarTribune:

The patient in his Duluth clinic was not responding to antibiotics, and now the stubborn infection in his intestines threatened to kill him. Then Aas found a similar case written up in a 1950s Norwegian medical journal.

The cure? Replace all the bacteria in the patient’s gut with a tiny dose of someone else’s stool.

A stool transplant? Was Dr. Aas serious? Yes, he most certainly was.

The “microbiome,” as it is known, is now the focus of a $115 million federal research project to investigate the symbiotic bond between humans and their bacteria.

Well, we’ve reported before that bugs can be good for us and that it’s possible to be too clean – but this puts a whole new perspective on things. From the National Institute of Health:

Within the body of a healthy adult, microbial cells are estimated to outnumber human cells by a factor of ten to one. These communities, however, remain largely unstudied, leaving almost entirely unknown their influence upon human development, physiology, immunity, and nutrition.

While the term “microbiome” may be relatively new in biomedical research, most people are familiar with some of the effects — both good and bad — that microbes can have on our health. Consider the example of the biggest reservoir of microbes in humans: the digestive tract. The human gut harbors many beneficial microorganisms, including certain bacteria called probiotics. There is evidence these probiotics, found in dietary supplements, yogurt and other dairy products as well as various soy products, can stimulate the immune system and improve digestive functions. In contrast, previous research suggests that variations in the composition of microbial communities may contribute to chronic health conditions, including diabetes, asthma, obesity and digestive disorders.

We need microorganisms to survive. It appears that the key is not so much to eliminate microogranisms from our bodies, but to keep them in the proper balance. Again from the Star Tribune story:

Aas’ patient 10 years ago had a common intestinal infection caused by a bacterium called C. difficile. It sometimes takes hold when patients get a dose of antibiotics for some other reason. These can destroy the population of beneficial intestinal bacteria, or flora, that digest food and provide nutrients to the body. Then the spores of C. difficile, which can lurk in the gut, flower and take over, producing a toxin that causes severe diarrhea and, in time, destroys the colon lining.

Often, a dose of a different antibiotic will suppress the infection. But sometimes C. difficile just keeps coming back.

C. difficile is one of a growing number of micro-organisms that have become resistant to antibiotics, while at the same time becoming more common and more virulent. According to the Mayo Clinic: Healthcare associated infections — illnesses you acquire during a stay in a hospital or longterm care facility — aren’t new. But in recent years, the infections have reached epidemic proportions in hospitals and nursing homes around the world. One of the most widespread and potentially serious of these illnesses is caused by the bacterium Clostridium difficile, often simply called C. diff or C. difficile. C. difficile bacteria are everywhere — in soil, air, water, human and animal feces, and on most surfaces. The bacteria don’t create problems until they grow in abnormally large numbers in the intestinal tract of people taking antibiotics or other antimicrobial drugs. Then, C. difficile can cause symptoms ranging from diarrhea to life-threatening inflammations of the colon. According to the Centers for Disease Control and Prevention, each year in the United States C. difficile is responsible for tens of thousands of cases of diarrhea and at least 5,000 deaths. And the problem is getting worse. The number of C. difficile infections doubled between 1993 and 2003, with most of the increase coming after 2000. C. difficile isn’t confined exclusively to hospitals. It’s also a growing problem among otherwise healthy people. And although the infection can usually be controlled with antibiotics, virulent strains of C. difficile are now appearing that resist treatment with common medications. Hence the need for a new cure.

Now, Rubin and Aas are researching which bacteria are the critical players in the hidden war inside the gut. If they can answer that, patients might one day get a pill with the right bacteria instead of a tube in their nose. In a refreshing bit of candor: Aas says he doesn’t know exactly why the stool transplant works. He presumes that the infusion of donated flora resets the bacterial balance in the gut and somehow keeps the C. difficile in check. Whatever the mechanism, it works 95 percent of the time. Neither group of researchers expects that finding the answer would result in a new, blockbuster drug. There are probably not enough severe cases for that kind of payoff. They are after different stakes — a better understanding of the relationship between humans and their bacteria. In an interview in the Washington Post, Aas stated that he views stool as an organ: It is normally considered waste product, but it is in a way an independent organ, like the kidney, and it contains thousands of different bacteria living in symbiosis. These bacteria are needed for normal health. When you use some antibiotics, some of this bacteria population gets destroyed. If you later get infected with Clostridium difficile colitis, there is this competitive battlefield in the colon, and without the necessary bacteria, Clostridium has the upper hand. So what we do is take normal stool from a normal person, make an extract of it, put it in a blender with water, take two tablespoons of that cocktail, and introduce it into the patient’s body. Fascinating stuff. We hope their research leads to a better understanding of the ecosystems inside and outside our bodies. It’s not just humans who are afflicted with this disease. Dogs and other animals also suffer from c. difficile. In June, 2006 the CDC reported that a toxin-variant strain of C. difficile was diagnosed in a healthy, 4-year-old toy poodle that was visiting patients in Ontario hospitals on a weekly basis. The canine isolate was indistinguishable from the major strain implicated in outbreaks of highly virulent c. difficile found in humans around the world. Although this was reportedly the first report of a human strain of c. difficile detected in a dog, many strains of the disease isolated from animals are indistinguishable from those associated with this disease in humans. Want to know more about c. difficile? Check out this great summary on the disease from from our friends over at Worms and Germs. And in the meantime – wash your hands, avoid taking unnecessary antibiotics – and don’t keep your house too clean.

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Entry filed under: dogs, health, minnesota, science. Tags: poop.