Dr Ben Mullish and Dr Julie McDonald explore the ins and outs of faecal microbiota transplants – it may sound unpleasant but this procedure is proving to be an effective way of treating chronic gut infections.
Most of us can name (or may have had first-hand experience of) a number of different bacteria that can cause serious gut infections, such as Salmonella or Campylobacter. However, what is less well-known is that we also have billions of bacteria living in our guts that normally do us no harm at all. Some actually have important contributions towards our health – including prevention of bacterial pathogens entering our gut and causing infections. Collectively, this huge population of microorganisms living inside our digestive tracts is often referred to as the ‘gut microbiota’. If anything happens to us that disturbs or kills off members of this gut microbiota – such as exposure to antibiotics, or surgery – then we have greater vulnerability to gut infections, and particularly from a form of bacteria called Clostridium difficile.
Antibiotics are the major risk factor for C. difficile infection (CDI), as loss of protective bacteria allows C. difficile to enter the gut unopposed, infect us, and produce toxins that inflame the large bowel. In the worst cases of CDI people need surgery to remove sections of the gut, and infection can be fatal in some individuals. Of particular concern has been the recent emergence of new strains of C. difficile that produce more toxin than previous strains, and which are also more resistant to the antibiotics traditionally used to kill it.
Since losing members of the gut microbiota makes someone vulnerable to CDI, could you treat the condition by taking bacteria from a healthy person’s gut and transferring them into the intestines of patients with CDI, with the aim of restoring the gut microbiota back to its original state? It is this idea that gave rise to a treatment called ‘faecal microbiota transplant’ (FMT). The procedure is pretty much what you would imagine – a stool sample is donated by one person, and part of it transplanted into another: