Weight gain after stool implant story shows importance of correct donors

In recent days the BBC has been more than a little interested in the tale of a woman from the United States who put on more than two-and-a-half stone after receiving a medical Faecal Transplant treatment using her daughter as a donor.

The patient in question was a 32-year-old lady with a case of Clostridium difficile infection that was resistant to all the drugs her doctors had tried.  For aesthetic rather than scientific reasons, the patient chose her own daughter to be her donor.  Her daughter was overweight at the time and on the path to obesity.

The Faecal Transplant was successful in resolving the potentially dangerous bacterial infection but a year later the woman’s body mass index (BMI) has risen from 26 to over 34.

This tale is why at the Taymount Clinic we have a very carefully designed Donor Selection Program and amongst other health factors, we only use donors whose body weight is normal, which means their BMI is 25 or less and who are in good shape.

Also, we analyse two distinct families of bacteria called Bacteroidetes and Firmicutes, using a DNA profiling process to look at their ratio.

In the case of this lady, the patient’s doctors were at a loss to explain her case, but the medics concerned faced a microbiological problem, which they appeared ill-equipped to answer.

Clinical research into weight gain following FMT was actually presented over a year ago in Nature magazine, the International Journal of Science, which illustrates clearly what happened in this lady’s case.  See link below.


Also, there are other medical and scientific articles about this relating to studies and trials carried out on mice where the researchers changed the ratio of Firmicutes and Bacteroidetes, which also exist in a delicate balance in the human gut.

The research found out that obese people had a higher ratio of Firmicutes groups against Bacteroidetes groups, where the reverse was found to be true in non-obese people.

To support this, the researchers took bacteria from an obese group of patients and transplanted them into the sterilised gut of mice allowing them to populate.

The mice very quickly developed obesity themselves.

Next they again sterilised the gut of these mice transplanted the microflora from non-obese people into them. This resulted in the mice quickly going from obese back to a normal weight.

This model was conducted a number of times under different scenarios allowing the mice to pass bacteria between themselves concluding that the ratio between Firmicutes and Bacteroidetes is critical in maintaining normal weight.

Whilst doctors are quick to point out that using a mouse model to prove a scientific theory does not automatically translate across to humans, microbiologists have been examining the profile of gut bacteria taken from both obese and slim people and are consistently finding significant differences.

We hope this research puts at ease the minds of those contemplating FMT.

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