Background: We analyzed the fecal microbiota profiles of patients with Crohn's disease (CD) at 4 inflammatory bowel disease (IBD) centers located in different districts in Japan.
Methods: Terminal restriction fragment length polymorphism (T-RFLP) analysis was performed in 161 fecal samples from CD patients and 121 samples from healthy individuals. The bacterial diversity was evaluated by the Shannon diversity index (SDI).
Results: There were no regional differences in the fecal microbiota profiles of the healthy individuals in Japan. A setting of similarity generated three major clusters of T-RFs: one included almost all the healthy individuals (118/121), and the other two clusters were mainly formed by CD patients at different stages of disease activity. The changes in simulated bacterial composition indicated that the class Clostridia, including the genus Faecalibacterium, was significantly decreased in CD patients with active disease and those in remission as compared with findings in the healthy individuals. In contrast, the genus Bacteroides was significantly increased in CD patients during the active phase as compared with findings in the healthy individuals. The genus Bifidobacterium was significantly decreased during the active phase of CD and increased to healthy levels during the remission phase. The bacterial diversity measured by the SDI was significantly reduced in CD patients during the active and remission phases as compared with findings in the healthy individuals. From the clinical data and T-RFLP analysis, we developed a logistic model to predict disease activity based on the fecal microbiota composition.
Conclusion: Dysbiosis in CD patients was shown by a multi-IBD center study. The feasibility of using the fecal microbiota profile as a predictive marker for disease activity is proposed.