Gut microbiota points to post-colectomy pouchitis risk

Last Updated: 2015-10-21

By David Douglas

NEW YORK (Reuters Health) - The composition of the microbiota in fecal samples before colectomy can help predict which patients will develop pouchitis within a year of ileal pouch-anal anastomosis (IPAA), according to Belgian researchers.

As Dr. Séverine Vermeire told Reuters Health by email, "It may prove useful to measure the presence or absence of this predictive signature in the stools in patients needing colectomy for ulcerative colitis. Patients who show the microbial signature predicting pouchitis might benefit from a close surveillance or even from immediate initiation of a preventive treatment with antibiotics or probiotics."

For their study, online September 30 in Gut, Dr. Vermeire of University Hospital Leuven and colleagues studied 21 patients. They collected fecal samples before colectomy and at predefined clinical visits up to 12 months after IPAA.

During this first year of follow-up, in patients developing pouchitis, there was a highly significant increase in Ruminococcus gnavus, Bacteroides vulgatus and Clostridium perfringens; there was a reduction in Blautia and Roseburia genera.

The team used this information to devise a score combining these bacterial risk factors. The presence of a high-risk species (B. vulgatus, R. gnavus or C. perfringens) and absence of the low-risk Roseburia spp or Blautia spp before colectomy were each scored as one point.

Having two or more risk factors had a sensitivity of 100% and a specificity of 63.6%. The positive predictive value was 66.7% and the negative predictive value was 100%.

"If patients at risk of developing pouchitis can be identified before colectomy, more targeted intervention studies can be performed," the researchers write.

Dr. Vermeire pointed out that future clinical trials are "necessary to investigate the most potent and effective treatment to prevent the development of pouchitis in these patients. These trials should include microbial analysis. An alternative option is to treat patients immediately before the resection by manipulation of the microbiota and thereby reverse the presence of a high-risk signature to a low-risk signature."

SOURCE: http://bit.ly/1KocG7l

Gut 2015.