Who would have thought it? How could anybody seriously suggest treating IBS with an inoculum of somebody else’s faeces? As a society, we are so aversive to the whole idea of poo, that many people do not even want to see their own faeces; they just flush them out of sight as quickly as possible. The whole idea is disgusting. Yet this is exactly what some doctors are proposing. Gastroenterologist, Dr Thomas Borody from Royal North Shore Hospital, Sydney has treated over 12000 patients with faecal microbial transplant (FMT) for over 20 years, and claims an 80% success rate.
FMT has become the gold-standard cost-effective treatment for the devastating antibiotic-associated colitis caused in the main by overgrowth with Clostridium Difficile. Inoculation with healthy bacterial flora from a surrogate can oust the marauding Clostridia and patients can recover within days after just one treatment. There has also been success with Ulcerative Colitis. So why should the same treatment not work for IBS? Among the major risk factors for IBS are treatment with courses of broad spectrum antibiotics and a severe attack of gastroenteritis, both of which can deplete the normal bacterial flora. Moreover, studies of the microbiome in IBS have demonstrated both depletion and instability.
Bacteria have been used to treat IBS for years, but the results are hardly overwhelming. Since there are so many different probiotics on the market, each one containing different combinations of bacteria in different delivery systems, it is difficult to conclude that any of them work. Moreover probiotics do not remain in the gut. They are rapidly swamped by the resident species and have to be administered every day if they are to have any effect. Many of the preparations contain lactobacilli, which can ferment milk under aerobic conditions and/or bifidobacteriacae, another facultative anaerobe that tends to colonise the gut of infants. It is not entirely that such relatively small doses of specific infantile bacteria made little lasting difference to the complex ecosystem of human colon. How much better to deliver a ready made culture in the form of faeces from healthy donors. If we can get over the ‘yuk’ factor, it makes perfect sense. And it seems to work.
Last year, a systematic review of reports and papers examining FMT in the treatment of IBS was published. Despite the small number of patients and differences in study design between the included studies, an improvement was seen in 58% of participating IBS patients. In one notable study, 9/12 patients experienced adequate relief of symptoms after the procedure and in 7 patients the results were sustained after a year. At the time of publication, results of properly randomised, double-blinded placebo controlled clinical trials of FMT were not available. This has now changed. This month, the first randomised control study of FMT was published on 83 patients with IBS by a group from Norway. The test inoculate, obtained from a surrogate was delivered by colonoscopy. The control was a suspension of a subjects own faeces. 36 out of 55 (65%) patients who received the novel inoculate showed a marked improvement after one treatment compared with 12/28 receiving the control autologous inoculate. This just achieved statistical significance (p = 0.049). Unwanted effects were minimal. One patient in the active group had transient nausea, three patients (2 in control group) experienced a brief episode of pain. Two patients, one in each, group suffered some leakage of the inoculate. Watch this space! Other studies will be published this year.
Early studies of FMT were carried out using donor faeces from a spouse or close relative, even though these might more likely to be carriers of infection. Faecal suspensions now tend to be harvested from volunteer donors, who need to be screened for previous infections, antibiotics. Both C. difficile and Salmonella spp can be found in carriers who have no bowel symptoms. Perhaps donors should also be screened for diet and stress since both may alter the microbiome to cause symptoms of IBS. If FMT takes off, perhaps inoculates might even be customised as lean meat microbiome, non fermenting microbiome or vegetarian microbiome.
There are problem of survival, storage and delivery. Many of the species in the human colon are strict anaerobes and may not survive outside the body in the absence of specific host factors. Freeze drying or suspending in an artificial culture medium could decimate the bacteria.
There is also the danger of pathogens. After an age in which we have always been told to wash our hands after going to the toilet, does it altogether seem wise to have somebody else’s stool inoculated into our guts?
And then there is the delivery. How should these bacteria be delivered? In the early days inoculates were administered by rectal tube or enemas. This is still an option. Colonic hydrotherapists are particularly interested in this route of delivery. Current home-made systems use nasogastric tubes, or even flavoured drinks, much as the Chinese used to do four thousand years ago to treat dystentery. The Bedouin had another solution: eating fresh camel dung. The orogastric or nasogastric routes would surely risk vomiting or choking, not to mention giving everyone small intestinal bacterial overgrowth. Other ideas include inserting suspensions or freeze dried faeces in capsules (otherwise known as crapsules).
I realise that if your IBS is making you desperate, you might try anything, even faecal microbial transplant. The early evidence looks promising: as good, if not better that many other treatments for IBS. Moreover, to make it more acceptable, researchers have even succeeded in produce a standardised bacterial filtrate that is colourless and odourless and at least as effective as the crude faecal inoculate.