A new case report published in the journal Open Forum Infectious Diseases reveals that a woman who was treated for a recurrent Clostridium difficile infection with the gut bacteria of an overweight donor quickly and unexpectedly gained weight herself following the procedure. The authors say the case suggests doctors should avoid using bacteria from overweight donors for such treatment.

Share on Pinterest A woman who received gut bacteria from an overweight donor – for the treatment of recurrent C. difficile infection – rapidly gained 34 pounds in the 16 months after the procedure.

Infection with C. difficile can cause inflammation of the colon, leading to diarrhea, fever, loss of appetite, abdominal pain and nausea.

According to the Centers for Disease and Prevention (CDC), C. difficile is responsible for around 337,000 infections and 14,000 deaths in the US each year. Elderly individuals and people with certain medical conditions are most at risk of C. difficile infection.

For primary C. difficile infection, antibiotics are the first port of call when it comes to treatment, and for most patients this is effective. Some patients, however, may experience recurrent C. difficile infection. In such cases, fecal microbiota transplantation (FMT) may be recommended.

FMT is a procedure in which a stool is collected from a donor free of C. difficile, and “friendly” gut bacteria are isolated from the fecal matter. This bacteria are then transferred to the recipient’s gut, with the aim of replacing the good gut bacteria that may have been suppressed by overpopulation of C. difficile.

The 32-year-old woman described in the case report underwent FMT at Newport Hospital, RI, in 2011 after experiencing recurrent C. difficile infection.

According to the report authors, including Colleen R. Kelly of the Warren Alpert Medical School at Brown University in Providence, RI, the woman weighed 136 pounds and had a body mass index (BMI) of 26 at the time of the procedure.

The donor bacteria used for transplantation came from the woman’s 16-year-old daughter, who was healthy but overweight – with a weight of 140 pounds, which later rose to 170 pounds, and a BMI of 26.4.