The Fecal Microbiome of IBD Patients Is Less Divertible by Bowel Preparation Compared to Healthy Controls: Results From a Prospective Study.

BACKGROUND

The fecal microbiome of patients with inflammatory bowel diseases (IBD) is characterized by longitudinal variability. It remains unknown if this is caused by decreased resilience of the microbiome to external factors. We investigated the influence of osmotic diarrhea induced by bowel preparation as a disruptive factor on the fecal microbiome in IBD patients and healthy comparators.

METHODS

We conducted a prospective, single-center study including IBD patients and healthy controls scheduled for colonoscopy with uniform bowel preparation. Fecal samples were collected at 7 time points prior, during, and until 3 months after the intervention. 16S rRNA was isolated from stool and sequenced using the Illumina technique.

RESULTS

Twenty-two IBD patients and 17 healthy controls were included in the study. Baseline diversity was higher in healthy controls. Bowel preparation longitudinally decreased alpha diversity and altered beta diversity and taxonomic composition in both groups. Alterations were more pronounced in healthy controls, and the microbial composition converged between the 2 groups. Bowel preparation resulted in an increased relative abundance of Anaerostipes and Coprococcus in both groups and in decreased relative abundance of Bifidobacterium and Clostridium sensu stricto in IBD patients and of Eubacterium hallii group and Ruminococcus in healthy controls. Changes largely restored to baseline composition within 1 week in both groups and remained stable thereafter.

CONCLUSIONS

Bowel preparation induced reversible short-term microbial perturbations which were less pronounced in IBD patients than in healthy comparators suggesting that a single external disruptive factor may have less impact on an already altered fecal microbiome.