A faecal transplant is like wild flower seeds in some soil

Keith S. Taber

I was listening to a podcast from 'Science Stories' (BBC Radio 4) about 'Lady Mary Montagu's Smallpox Experiment', where Naomi Alderman described how the aforementioned Lady Mary Wortley Montagu brought the practice of opening veins to introduce some smallpox into the body, as a way of protecting against the deadly disease, back from Turkey to Britain.

Flush or donate?

This was compared with the process of faecal transplantation which was apparently first used in China, and is increasingly being seen as a valuable treatment for some gut disorders. This is the process of ingesting, under carefully controlled conditions, some human faeces – either some of your own carefully preserved (for example, some cancer patients have a sample collected and stored before starting chemotherapy), or from some donor who is willing to offer some of their own. Unlike some other donor procedures (such as kidney donation) this is non-invasive and concerns material most of us just dispose of anyway!

Tim Spector, Professor of Genetic Epidemiology at Kings College, London explained the significance of the gut microbiome, the community of something like 100 trillion microbes that typically occupy a human gut. The importance of these organisms for human health is increasingly being appreciated.

Treating Clostridium difficile infection

Disturbances of the gut microbiome can lead to ill health. One particular example is the condition known as Clostridium difficile infection ('C. diff') – which is commonly experienced in hospitals when patients have extensive courses of antiobiotics – which can sadly kill the useful gut microbes as well those disease-causing organisms being targeted. Clostridium difficile (being itself unaffected by many commonly used antibiotics) can in these circumstances reproduce rapidly and vastly increase its numbers. This is problematic as the organism releases a toxin.

C. diff infection can lead to the sufferer needing to visit the toilet urgently and repeatedly – many times each day. This is not only undesirable in itself, but interferes with getting nutrition from food (if the person has any appetite to eat), and leads to dangerous dehydration – and can have other complications. So, this is a very serious condition, and it is readily transmitted from one person to another.

"C. difficile is an infectious Gram-positive spore-forming bacillus microorganism of the gastrointestinal tract, and its toxin expression causes gastrointestinal illness with a wide spectrum of severity, ranging from mild diarrhea to pseudomembranous colitis, toxic megacolon, sepsis-like picture and death…"

Bien, Palagan & Bozko, 2013: 53

Many people have a low level of Clostridium difficile specimens in their gut normally, but as one small part of the much larger and diverse population of gut microbes – in which context they cause no problems.

"C. difficile does not cause any significant disease when it is present in small numbers. However, disturbance of the normal intestinal flora (dysbiosis) by several potential causative factors may result in unlimited [sic] expansion of C. difficile in the microbiota, leading to inflammation and damage of the gut mucosa…"

Bien, Palagan & Bozko, 2013: 56

Someone who has suffered from C. diff infection needs a way to repopulate their gut with a good range of the usual different microbes. And that is when consuming a sample of a healthy person's excrement can be useful. (This is of course done under medical direction and supervision, both to maintain hygiene and to ensure the donor does not have medical conditions that might be passed on with the sample.)

A teaching analogy for faecal transplantation

This was all explained by Prof. Spector using an analogy.

Analogies are comparisons where a less familiar, and perhaps abstract or counterintuitive, concept is explained in terms of something familiar that can be seen to have a similar conceptual structure (see the figure). Analogies are commonly used in science teaching and public communication of science (as here in a radio programme) to introduce scientific ideas.

(Read about science analogies)

How does your garden grow?

Prof. Spector developed a comparison between the different microbes found in the gut, and the plants growing in a garden:

"These nasty infections are the most extreme, if you like, that pretty much wipe out most of our normal species. So … we might, say, start with a thousand species and people [with C. diff] might be down to just ten or so, different ones and so nasty ones take over. It's a bit like a garden that has gone very badly wrong and you have put too much herbicide all over it and it looks like an Arizona back yard with a few burning tyres in it. It's very easy for things to take over that and what we want to get, is by putting these bugs in there, to create a really healthy garden that gets back to normal that looks like a nice English country garden with lots of blooms, and really good soil, and lots of plants interacting with each other, and that's the way to think about these microbes, but to do that, to get to this nice rosy picture of a country garden you have to go through yucky stages first"

Prof. Tim Spector – From 'Lady Mary Montagu's Smallpox Experiment'

So the idea of taking a sample of someone else's excrement into our own gut may seem "yukky" – and is definitely NOT recommended without proper procedures and supervision – but may sometimes be a sensible and beneficial medical treatment. Just think of it as resewing the garden of the gut with a nice selection of seeds that will give rise to a diverse selection of colourful blooms.

Naomi Alderman: Instead of poo, we could think to ourselves, 'wild flower seeds'

Tim Spector: It's wild flower seeds with a bit of soil in it as well, so they have come in their own pot [sic] if you like.

From 'Lady Mary Montagu's Smallpox Experiment'

Work cited:

• Bien, J., Palagani, V., & Bozko, P. (2013). The intestinal microbiota dysbiosis and Clostridium difficile infection: is there a relationship with inflammatory bowel disease? Therapeutic advances in gastroenterology, 6(1), 53-68. doi:10.1177/1756283X12454590 https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3539291/