Ileal microbiota predict recurrence in CD patients after resection

A new study, led by researchers from Saint Antoine Hospital, in France, reveals that ileal mucosa-associated microbiota may help predict recurrence in patients with CD after ileocecal resection [1].

Recurrence of inflammatory lesions is frequent in patients undergoing ileal resection for Crohn’s disease (CD), although there is not a single clinical risk factor that can be used as a perfect predictor of early postoperative endoscopic recurrence. The researchers of this study sought a microbiotic biomarker to predict recurrence. To this end they catalogued the ileal mucosa-associated microbiota by using ribosomal 16S sequencing at the time of surgery and/or at the time of postoperative endoscopic evaluation (about 6 to 12 months after surgery) in 201 patients from 9 centres in the prospective REMIND cohort. Not surprisingly, antibiotics treatment within one month before surgery had a dramatic impact on microbiota composition (P< 0.0001) and diversity (Shannon index mean 4.3±0.1 vs 3.7±0.2, P=0.006).

The ileal mucosa-associated microbiota exhibited major changes following CD surgery that differed between the time of surgery and the time of postoperative endoscopic evaluation. Specifically, changes included a decrease in beta diversity and a decrease in the Gammaproteobacteria class, an increase in the Alphaproteobacteria class, a decrease in the Bacilli class and an increase in the Clostridiales order.

Compared with patients who did not recur, however, endoscopic recurrence was associated with a high abundance of bacteria from the Gammaproteobacteria, the Ruminococcus gnavus group and Corynebacterium genera (Area under the curve: 97.1% [93.8%-100%] and 81.0% [60.8%-100%] in the whole population and in the validation set respectively). In contrast, patients without endoscopic recurrence at 6 to 12 months after surgery showed increased levels of bacteria from the Lachnospiraceae families, such as the Roseburia, Blautia, and Dorea genera.

In conclusion, ileocecal resection and endoscopic recurrence are associated with changes in ileal mucosa-associated microbiota, which may be applied for prognostication.

1. Sokol H et al. UEG Week 2019, Abstract OP209.

Posted on 23 October 20198 April 2024