It has recently become clear that each one of us is more microbe than human—at least when it comes to the number of cells in our bodies. The bacteria that swarm through our guts, across our skin, and in every orifice you have outnumber our human cells by at least 10 to 1, though their much-smaller size keeps that from being too obvious.
Having the right balance of these bacteria is an important factor in health, and when they get out of whack, it can be fatal. Take the case of Clostridium difficile infections: when these bacteria get established in people’s guts, they can disrupt the balance of other microbes and cause diarrhea so constant and severe that patients die. Antibiotics are not as effective against C. difficile as they used to be, and little by little, doctors have been giving patients in danger of losing their lives transplants of bacteria from healthy people’s guts. These treatments, called fecal transplants, involve collecting samples from donors, testing it to guard against giving patients other diseases, and administering it to the patient, during a colonoscopy or by other methods.
And it works. Fecal transplants have proven extremely effective for patients who had few or no other options. This, in spite of the fact that we don’t really understand, when it comes to the body’s microbes, what “normal” is. In fact, there’s evidence that at least in some parts of the body, one’s microbial complement, or microbiome, is wildly personal. In one dramatic example last year, a survey of the vaginal microbiome of 32 women showed that the bacteria varied widely among subjects and over time, with some women’s populations remaining relatively stable for the whole 16-week study period and others growing completely unrecognizable in a matter of days. Though a considerable amount of money and time is being spent on the problem of what a healthy microbiome is, how it gets disturbed, and what we can do to fix it, reports have revealed the problem to be almost fractally complex: It doesn’t get much simpler the deeper you look.
Though there’s still a lot we don’t know, treatments that focus on the microbiome, especially fecal transplants, are being talked about ever more widely and more seriously. Earlier this month, the FDA announced that it will require that all doctors and institutions that wish to provide fecal transplants send in an Investigational New Drug (IND) application including a detailed description of their procedure. They then must wait 30 days to get the go-ahead, or the no-go, from the agency.
This is the agency’s first real move to bring fecal transplants under its authority, and opinions on its helpfulness are mixed: Doctors who provide the procedure are worried that this is a monkey wrench that will add expense and time-consuming red tape to a potentially life-saving procedure that already is not covered by insurance. And the FDA hasn’t made public what it’s looking for in treatments, so doctors don’t know what how to help ensure they receive permission. INDs are usually handled by drug companies looking to test out a potential new product, not by doctors or hospitals, so this situation is posing unusual challenges. (Here’s a great, detailed post about the obstacles to commercializing fecal transplants.)
Over the long haul, though, it could be a good thing that the FDA wants to regulate fecal transplants. “It only takes one self-taught cowboy passing as a physician to poison the well for the rest of reputable clinical researchers,” wrote Bernat Olle at FierceBiotech in April. Although we’re just beginning to learn how each person’s unique microbiome relates to their health, fecal transplant seem to be a remarkably positive treatment. It would be good to try keep it that way, even if it means slowing down to figure out how to safeguard the practice from carelessness or duplicity.
Veronique Greenwood is a former staff writer at DISCOVER Magazine. Her work has appeared in Scientific American, Popular Science, and the sites of Time, The Atlantic, and The New Yorker. Follow her on Twitter here.