A woman who received a fecal transplant from an overweight donor is said to have experienced rapid weight gain following the treatment.
Fecal microbiota transplants (FMT) are used to treat chronic infections such as Clostridium difficile, which can be life threatening in sever cases, the Infectious Diseases Society of America reported. The event suggests physicians should avoid donors who are overweight and raises questions about the extent to which gut bacteria influences the metabolism.
At the time of the fecal transplant in 2011 the woman weighed a healthy 136 pounds and had a Body Mass Index (BMI) of 26. The woman received a fecal transplant from her overweight teenage daughter, effectively curing her infection. Sixteen months later the woman had reached 170 pounds and her BMI was up to 33, making her clinically obese.
"We're questioning whether there was something in the fecal transplant, whether some of those 'good' bacteria we transferred may have had an impact on her metabolism in a negative way," said Colleen R. Kelly, of the Warren Alpert Medical School of Brown University, who wrote the case report with Dr. Neha Alang of Newport Hospital in Rhode Island.
Past animal studies have shown the transfer of gut bacteria from obese to normal-weight mice caused weight gain.
The researchers noted the FMT was not the only possible cause of the woman's weight gain. The patient had been treated with several antibiotics for a Helicobacter pylori infection and other possibilities include "genetic factors, aging, and stress related to illness." It is also important to note that the woman had never been overweight before.
"Careful study of FMT will advance knowledge about safe manipulation of the gut microbiota," the researchers wrote. "Ultimately, of course, it is hoped that FMT studies will lead to identification of defined mixtures of beneficial bacteria that can be cultured, manufactured, and administered to improve human health."
The findings were published in a recent edition of the journal Open Forum Infectious Diseases.
