Published online Apr 7, 2018. doi: 10.3748/wjg.v24.i13.1464
Peer-review started: January 10, 2018
First decision: February 5, 2018
Revised: March 5, 2018
Accepted: March 7, 2018
Article in press: March 7, 2018
Published online: April 7, 2018
Inflammatory bowel disease (IBD) is generally defined by two nonspecific inflammatory disorders, Crohn’s disease (CD) and ulcerative colitis (UC), which are characterized by chronic persistent inflammation of the intestinal mucosa lining the intestinal tract. Recently, distinctive microbial composition and its interaction with the host immunological response are believed to play critical roles in the pathogenesis of IBD. Although the intestinal microbial composition of Western IBD patients has been extensively studied, there are conflicting reports about changes of the bacterial abundance. What’s more, the intestinal microbial profiles of Chinese IBD patients are not well characterized. In the present study, we use 16S rDNA amplicon-based analysis to analyze the alterations of fecal microbiota in Chinese patients with IBD.
Although the microbial community is gaining increasing attention for its influence on IBD, there is a lack of data on global alteration of microbiota in Chinese patients and the relationship is poorly understood. This study would characterize the important differences of fecal microbiota between Chinese IBD patients and healthy controls based on a 16S rDNA sequencing analysis, hoping to explore which kinds of the microbiota could be involved in the pathogenesis of IBD or providing important references for diagnosis or treatment of IBD.
The research aimed to investigate the differences in quantity, diversity and similarity of the fecal bacterial population taken from Chinese IBD patients at different stages of disease and healthy individuals.
Twenty-nine IBD patients (11 active CD, 4 inactive CD and 14 active UC patients) from the First Affiliated Hospital of Nanjing Medical University (Jiangsu, China) and 13 sex and age well-matched healthy individuals were enrolled in the study. 16S rDNA amplicon-based sequencing was used to analyze the fecal microbiota of each sample.
In this study, community richness (chao) and microbial structure in IBD were significantly different from those in normal controls. The relative abundance of Bacteroidetes in the active CD group was significantly lower than that in the inactive CD group, and it showed a negative correlation with Crohn’s disease activity index (CDAI). At the phyla level, the abundance of Proteobacteria was significantly higher in IBD than in controls. At the genera level, 8 genera in CD and 23 genera in UC (in particular, the Escherichia genus) showed significantly greater abundance as compared to that in normal controls.
Our study presented a comprehensive analysis of fecal microbiota in the gut of Chinese patients with IBD. Significant differences in microbial composition of patients with IBD and controls were observed. Additionally, the negative correlation between Bacteroidetes and CDAI suggested that Bacteroidetes might have a negative impact on development of inflammation.
Fecal microbial examination is noninvasive and easily collected compared with the mucosal biopsy, which may increase the risk of unexpected bleeding.However, the mucosa-associated microbiota is believed to directly affect epithelial and mucosal function. In the future, both the fecal and mucosa-associated microbiota should be investigated together to better understand the role of the intestinal microbiota in health and disease.