Transplanting what?

For some patients with persistent, recurring colonic infections, doctors have turned to fecal bacteriotherapy – transplanting a stool sample from a healthy donor into the patient’s colon.  Pediatrics recently reported the successful use of this technique to cure a 2-year-old girl suffering from a many-months-long infection of Clostridium difficile, using her father as the donor.  After the transplant, the girl’s symptoms resolved within 36 hours.

Clinicians have hypothesized that bacteriotherapy works by reestablishing the normal population of microflora in a patient’s colon, but have previously been unable to test this due to limits in microbiology. Now, The New York Times has reported another successful bacteriotherapy treatment – this time with a new development. 

A woman had lost 60 pounds over the course of an 8-month-long C. difficile infection, and her clinician, Dr. Khoruts, turned to bacteriotherapy as a last resort.  The procedure was again successful, resolving the patient’s diarrhea within one day.  However, Dr. Khoruts did something different from the other cases – he took genetic snapshots of the patient’s colonic microflora before and after the fecal transplant.  He found that before the transplant, the population was severely deficient in Firmicutes and Bacteroidetes bacteria, but 14 days after the transplant, the colonic microflora was dominated by Bacteroides species strains – just like the healthy donor’s.

Dr. Khoruts’s results strongly support the idea that fecal bacteriotherapy normalizes the bacterial population in the colon, resulting in restoration of normal bowel function.  Because he focused on which bacteria were present before and after transplantation, his work opens up the possibility of refining this therapy to use specific microbes grown within a controlled environment.  Not only would that kind of scientific advance make the therapy more widely available, but it would eliminate the risks associated with human donor specimens. 

Researchers are just beginning to understand the millions of bacterial species that live in and on humans, and their role in keeping us healthy. This field of research may present many more opportunities to develop novel therapies, and the mounting evidence of successful fecal bacteriotherapy points the way to future clinical studies.

Pediatrics article: http://www.pediatricsupersite.com/view.aspx?rid=65701
New York Times article: http://www.nytimes.com/2010/07/13/science/13micro.html
Dr. Khoruts's Journal of Clinical Gastroenterology abstract: http://journals.lww.com/jcge/Abstract/2010/05000/Changes_in_the_Composition_of_the_Human_Fecal.10.aspx