One of the more bizarre new medical treatments currently under investigation is a transplant of gut bacteria. This sounds, on the face of it, pretty weird. Even weirder when you talk of faecal transplants. Faeces are smelly things we want to get rid of, aren’t they? Why would anyone want a transplant of someone else’s?
There are some scientists who believe that gut bacteria (that live, mainly, in the colon) are so important that they should be viewed as an additional body organ. Others might argue that it is possible to live your life without a colon (after cancer surgery for instance) so that neither the contents nor the colon are essential.
Some people find themselves wretchedly ill if their normal gut bacteria are killed off. Imagine, if you will, a dense tropical forest with many species of plant, all flourishing away in leafy harmony. Then someone sprays the forest with strong herbicides, killing off every leaf and shoot. This allows an aggressive weed to invade and flourish. This is the effect that can occur in the colon after treatment with broad-spectrum antibiotics. The original infection elsewhere in the body may be cured, but the patient cannot return to health because they are suffering the miseries of diarrhoea. At its most serious, this diarrhoea is caused by Clostridium difficile, which can cause death in weak patients.
Probiotics may be protective but they are not a cure. If the normal gut bacteria have all been killed, yoghurt bacteria are no replacement. What the colon needs is a blend of dozens of harmless species of gut flora.
The idea of a gut bacteria transplant is a fairly new one. The process is to take a faecal sample from another person, mix it with water to produce an enema, and administer it to the patient. Relatives may be used as donors, because they are most likely to share the bacterial blend that the patient's immune system normally lives with.
In early studies with small groups of patients the results are encouraging.
In a systematic review of small trials, involving 124 patients, (83%) improved immediately after the first FT procedure, and some patients stayed diarrhoea free for several months or years. There is still a need to conduct controlled trials to compare faecal transplant with the standard treatment.
Although the idea may seem a little weird, it would indeed be wonderful if this kind of treatment did prove effective in curing this distressing and dangerous condition.
Aliment Pharmacol Ther. 2012 Apr;35(8):865-75.
Guo et al