The thought of transplanting another person’s feces into your colon may sound uncomfortable and understandable enough. Stools are a foul-smelling mixture of water, undigested food, dead and living bacteria and other cells and substances. However, the live bacteria in feces have proven their worth in the treatment of diseases and disorders of the digestive tract. This is why doctors have been transferring feces from healthy donors to sick patients for years – usually by colonoscopy, enema or pill – to restore bowel health.
The concept is relatively simple: Good bacteria from donated feces will colonize the patient’s gut if the recipient’s microbiome is out of balance and will outcompete any problems that cause bacteria. For example, healthy stool bacteria can be used to treat an infection Clostridioides difficult bacteria that can infect the human colon and cause mild to life-threatening diarrhea. In clinical trials, fecal microbiotate transplants are estimated to be more than 90 percent effective by clearing C. diff infections. And just last month, researchers in Norway wrote in the journal Gastroenterology that patients with irritable bowel syndrome (IBS) suffer less from bloating, stomach cramps and constipation after being treated with a fecal transplant – even three years after receiving it.
David Ong, a gastroenterologist at Mount Elizabeth Hospital in Singapore, sees even greater potential for these treatments as intestinal microbes interact with our brain and other organs. Ong, who in 2014 was the first doctor in Singapore to perform a fecal transplant on a patient infected with C. diff, says recent studies suggest that the intervention could also help people with inflammatory bowel disease or obesity, or those on autism spectrum with intestinal problems related to picky eating. There is currently more than 100 clinical trials examines the effect of fecal transplants on conditions ranging from depression to epilepsy and Covid-19 to cancer.
“Gen is what you were born with and that is what it is,” Ong says. “But the gut microbiome is something you can manipulate. And if you can manipulate it to a good result in terms of disease, it’s excellent.”
However, there is just the small question of finding the right stool. In addition to working as a gastroenterologist, Ong co-founded the startup Amili, which houses what is currently Southeast Asia’s only fecal transplant bank. It has collected more than 1,000 stool samples over the past three years. However, most willing donors are excluded after completing questionnaires and having their feces, blood, and saliva tested in the laboratory.
Lifestyle, diet, medical history – including the use of antibiotics that can kill intestinal bacteria – and how someone was born can all exclude people. (Newborns born through the vagina pick up their first gut bacteria from their mother as they move through the vaginal canal and show greater microbial diversity than those delivered by caesarean section.) In the Norwegian trial, the stool samples used to treat 87 patients with IBS came from one donor: A 36-year-old man born vaginally; ammet; was a non-smoker; had only been treated with antibiotics a few times; trained regularly; and ingested large amounts of protein, fiber, minerals and vitamins. In general, when a donor is considered healthy enough, laboratory technicians will examine their stool sample. The technicians are looking for various microbiomes and especially bacteria that are known to compete with harmful bacteria.