Division of Gastroenterology and Hepatology, Department of Medicine, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599-7080, USA.
Neurogastroenterol Motil. 2012 Jun;24(6):521-30, e248. doi: 10.1111/j.1365-2982.2012.01891.x. Epub 2012 Feb 20.
The intestinal microbiota has been implicated in the pathophysiology of irritable bowel syndrome (IBS). Due to the variable resolutions of techniques used to characterize the intestinal microbiota, and the heterogeneity of IBS, the defined alterations of the IBS intestinal microbiota are inconsistent. We analyzed the composition of the intestinal microbiota in a defined subgroup of IBS patients (diarrhea-predominant IBS, D-IBS) using a technique that provides the deepest characterization available for complex microbial communities.
Fecal DNA was isolated from 23 D-IBS patients and 23 healthy controls (HC). Variable regions V1-V3 and V6 of the 16S rRNA gene were amplified from all samples. PCR products were sequenced using 454 high throughput sequencing. The composition, diversity and richness of microbial communities were determined and compared between D-IBS and HC using the quantitative insights into microbial ecology pipeline.
The contribution of bacterial groups to the composition of the intestinal microbiota differed between D-IBS and HC. D-IBS patients had significantly higher levels of Enterobacteriaceae (P = 0.03), and lower levels of Fecalibacterium genera (P = 0.04) compared to HC. β-Diversity values demonstrated significantly lower levels of UniFrac distances in HC compared to D-IBS patients. The richness of 16S rRNA sequences was significantly decreased in D-IBS patients (P < 0.04).
CONCLUSIONS & INFERENCES: Our 16S rRNA sequence data demonstrates a community-level dysbiosis in D-IBS. The altered composition of the intestinal microbiota in D-IBS is associated with significant increases in detrimental and decreases in beneficial bacterial groups, and a reduction in microbial richness.
肠道微生物群与肠易激综合征（IBS）的病理生理学有关。由于用于描述肠道微生物群的技术分辨率不同，以及 IBS 的异质性，IBS 肠道微生物群的定义改变并不一致。我们使用一种可对复杂微生物群落进行最深入特征分析的技术，分析了一组特定的 IBS 患者（腹泻型 IBS，D-IBS）的肠道微生物群组成。
从 23 例 D-IBS 患者和 23 例健康对照者（HC）的粪便中提取 DNA。从所有样本中扩增 16S rRNA 基因的可变区 V1-V3 和 V6。使用 454 高通量测序对 PCR 产物进行测序。使用定量微生物生态学分析管道（quantitative insights into microbial ecology pipeline）确定和比较 D-IBS 和 HC 之间微生物群落的组成、多样性和丰富度。
细菌群落在 D-IBS 和 HC 之间的肠道微生物群组成不同。与 HC 相比，D-IBS 患者的肠杆菌科（Enterobacteriaceae）水平明显更高（P = 0.03），而粪便杆菌属（Fecalibacterium）水平明显更低（P = 0.04）。β多样性值表明 HC 中 UniFrac 距离明显低于 D-IBS 患者。D-IBS 患者的 16S rRNA 序列丰富度明显降低（P < 0.04）。
我们的 16S rRNA 序列数据表明 D-IBS 存在群落水平的失调。D-IBS 中肠道微生物群的改变与有害细菌群的显著增加和有益细菌群的减少以及微生物丰富度的降低有关。
