I was talking to my sister and four-year-old nephew the other day and my sister prompted him to tell me what he wanted to study when he grew up. He looks right at me and answers “poop”. Totally funny coming from the boy who really is obsessed with his own poop, but as a scientist, I responded that I could tell him lots about poop and asked, “what about poop are you interesting in studying?” His response, “All of it.” Well, I agree. Poop is far more interesting than we give it credit for. In this series of posts, I will share with you all the interesting stuff I know about poop. The first post was facts about poop and post is about using poop as a cure for diseases. Let’s get down and dirty…
Changes in the percentage of different bacterial species in found in patients with various diseases compared to healthy control. From a review in Nature Reviews Microbiology
Your gut is filled with bacteria – estimates of over 100 trillion bacteria – weighing nearly 3 pounds! These bacteria are essential to help digest food and produce vitamins. These bacteria are also protective against pathogens, like other bad infectious bacteria or viruses. By studying the proportions of different gut bacterial species, scientists have found that the percentages of these bacterial species is different in patients with various diseases . Although it isn’t clear if the changes in the gut mircobiome are a cause or consequence of the disease, scientists and clinicians are exploring whether changing the balance of bacteria back to normal can cure (or reduce the symptoms) of these diseases.
C. Diff bacteria
In one particular case, it’s clear that a change in the gut microbiome is the cause of the disease and that’s Clostridium Difficile (also known as C. Diff) infection. This infectious bacteria releases toxins that cause mild but annoying symptoms like watery diarrhea 2-3 times per day with abdominal pain or tenderness, but can lead to more severe life-threatening issues like watery diarrhea over 15 times per day or creating a hole in the intestines. C. Diff is responsible for ~1% of all hospitalizations per year (>330,000 patients per year) and > 20,000 deaths per year and costs over $3.2 billion dollars for care. The elderly, hospitalized patients or patients taking antibiotics are most at risk for transmission, which is caused by fecal-oral transmission or through hospital workers (since the C. Diff spores aren’t killed by alcohol).
Although an annoying, deadly and expensive disease, C. Diff infection has recently gotten worse. C. Diff infection is becoming more common and relapse after treatment is more frequent. The bacteria has become more virulent with an increased capacity to produce the symptom-inducing toxins while at the same time becoming resistant to the most common antibiotics used to treat this infection: metronidazole and vancomycin.
So what does this have to do with the microbiome? Well, the normal bacteria in your gut can protect against C. Diff infection. C. Diff is found in 2-5% of all people who aren’t sick, because the gut microbiome can inhibit C.Diff growth or toxicity directly by making antimicrobial peptides or indirectly by creating an inhospitable environment for C. Diff to grow. Because of this, scientists thought – what if we just fixed the microbiome in C. Diff infected patients so that it’s normal again? And how would they do that? Fecal (POOP) transplant!
Although you may not be aware, there is a long and storied history of using poop as a treatment – primarily though the eating of poop. Yes, this is gross, but maybe if we use the official name for eating poop it will sound less gross? Coprophagy is the consumption of feces, with the distinctions of heterospecific coprophagy being eating feces of other species, allocoprophagy being eating feces of other individuals, and autocoprophagy being eating your own feces. If you have a dog, you know that they love eating poop (their own, cats poop, random poop, all poop really) and so do lots of other animals. At this point (if I haven’t lost you), you may be wondering why in the world would any animal or person eat poop?? It can help in the development of the GI tract by helping colonize the gut with bacteria, in developing resistance to pathogens, or in obtaining nutrients. In humans the practice goes back to 300AD in China where fresh, fermented, dried or infant-derived feces, charmingly named “yellow soup”, was used to treat multiple food poisoning or severe diarrhea. In 1696, Christian Paullini wrote a book on the medical uses of human and animal feces and in 1958 the first modern description of a fecal transplant was described to treat pseudomembranous colitis.
How does fecal transplant work today? The goal is to recolonize the patient’s gut with “normal” gut bacteria. To get this “normal” gut bacteria, you need a donor. Donors are often family or friends of the patient who are healthy and don’t have any recent antibiotic use. There is some testing (costing $500-$2000) required to make sure that the poop doesn’t contain particular bacteria or viruses. Then the poop is prepared for transplant. 50-60 grams of stool is added to a liquid like saline or milk and mixed together in a blender to create a liquid slurry (often patients are requested to provide their own blender). The slurry is then filtered through a coffee filter or metal strainer to remove particulates.
The feces mix then needs to get into the patient’s gut – and this can be done in a few different ways.
- Naso-duodenal – from the nose into the stomach using a tube. Although fast and 76% effective, it’s not palatable and often has disgusting side effects like vomiting
- Transcolonoscopic, which invloves drizzling the fecal mixture out of a colonoscpy tube in the large and small intestines. 89% effective, this method puts the poop directly where it needs to be.
- Enemas are also highly effective (95%) and are both cheap and safe. It can be performed at home, but it isn’t recommended.
New methods continue to be developed for fecal transplant to decrease the “gross” factor. The feces has been dried out and turned into pills. This is less smelly, but requires ingestion of 24-35 capsules and is more expensive. Scientists are also trying to culture the correct bacteria mixture in the lab so that a poop donor and poop sample preparation aren’t needed. The best part about this method is that scientists have dubbed it “rePOOPulating” the gut! Until then, a new business of stool biobanks like OpenBiome are cropping up to meet the need of poop for fecal transplants. For $500, your doctor can request a poop sample for fecal transplant.
For everyone who is completely grossed out right now, it’s important to point out that in patients with C. Diff, this treatment has been over 90% effective in recurrent infections whereas all other treatments were less than 40% effective. Patients are completely on board for this treatment. The biggest issue has been doctors who are grossed out and getting them to use poop to treat these horrible diseases.
So next time you look at your poop as you flush it down your toilet, remember how useful poop can be and knowing “what brown can do for you.”