Involvement of shared mucosal-associated microbiota in the duodenum and rectum in diarrhea-predominant irritable bowel syndrome.

Most studies of diarrhea-predominant irritable bowel syndrome (IBS-D) focused on microbiota dysbiosis in a single segment of the intestine such as the colon. However, the intestine as a whole is involved in IBS-D and knowledge about the role of microbiota shared by the duodenum and rectum in IBS-D is limited. Here, we investigated the characteristics of mucosal microbiota shared by the duodenum and rectum in IBS-D patients. We collected duodenal and rectal mucosal samples from 33 adult IBS-D patients and 15 healthy control (HC) subjects. The 454 pyrosequencing method and multiple bioinformatics analyses were used to examine bacterial 16S rRNA. Clinical data including symptoms and Bristol Stool Form were analyzed. Mucosal microbiota in duodenal samples differed from rectal samples in HC, while less difference was shown in IBS-D. More numbers in terms of shared operational taxonomic units and genera found in IBS-D compared with HC. The frequency of genera in the duodenum and rectum of HC differed from that of IBS-D. We identified 24 genera shared in the duodenum and rectum, which both changed dramatically in IBS-D. Among these 24 genera, half had similar trends in frequency differences, and the other half had opposite trends. The frequency of Faecalibacterium and Hyphomicrobium were associated with clinical data of IBS-D patients. Shared mucosal-associated microbiota in the duodenum and rectum appear to contribute to the etiology and pathophysiology of whole intestine of IBS-D and to be potential therapeutic targets.

Li G ，Yang M ，Jin Y ，Li Y ，Qian W ，Xiong H ，Song J ，Hou X ... -  《-》

Duodenal and rectal mucosal microbiota related to small intestinal bacterial overgrowth in diarrhea-predominant irritable bowel syndrome.

Small intestinal bacterial overgrowth (SIBO) has been proposed as an etiologic factor in irritable bowel syndrome, particularly the diarrhea-predominant subtype (IBS-D). We aimed to identify potential intestinal microbial pattern in IBS-D patients with SIBO. Diarrhea-predominant irritable bowel syndrome patients fulfilling Rome III criteria were recruited and randomly divided into an exploratory cohort (57 cases) and a validation cohort (20 cases). SIBO was identified according to standard glucose hydrogen breath test. For 16S rRNA gene sequencing, samples of duodenal mucosa, duodenal fluid, rectal mucosa, and fresh feces were collected and performed. The α and β diversity, as well as differences in microbial composition and function, in SIBO+ and SIBO- IBS-D subjects were evaluated. The microbial diversity and composition obviously differed between SIBO+ and SIBO- IBS-D in duodenal and rectal mucosa but not in duodenal fluid and fresh feces. For rectal mucosal microbiota, it displayed markedly reduced aerobe and Gram-negative bacteria and increased facultative anaerobe and Gram-positive bacteria, moreover, altered functions of microbial metabolism in SIBO+ IBS-D. Significantly higher rectal mucosa-related microbial dysbiosis index was observed in SIBO+ IBS-D, and a cut-off value at -0.37 had a sensitivity of 56.55% and specificity of 90.91% to identify the SIBO in IBS-D subjects. Mucosal microbiota, rather than luminal bacteria, has a more apparent dysbiosis in SIBO+ IBS-D patients relative to those without SIBO. Rectal mucosa-associated microbiota may act as a potential predictor of SIBO in IBS-D patients.

Yang M ，Zhang L ，Hong G ，Li Y ，Li G ，Qian W ，Xiong H ，Bai T ，Song J ，Hou X ... -  《-》

Understanding of the Site-Specific Microbial Patterns towards Accurate Identification for Patients with Diarrhea-Predominant Irritable Bowel Syndrome.

Zhu X ，Hong G ，Li Y ，Yang P ，Cheng M ，Zhang L ，Li Y ，Ji L ，Li G ，Chen C ，Zhong C ，Jin Y ，Yang M ，Xiong H ，Qian W ，Ding Z ，Ning K ，Hou X ... -  《Microbiology Spectrum》

Fecal and Mucosa-Associated Intestinal Microbiota in Patients with Diarrhea-Predominant Irritable Bowel Syndrome.

Maharshak N ，Ringel Y ，Katibian D ，Lundqvist A ，Sartor RB ，Carroll IM ，Ringel-Kulka T ... -  《-》

Characteristic dysbiosis of gut microbiota of Chinese patients with diarrhea-predominant irritable bowel syndrome by an insight into the pan-microbiome.

Wang Z ，Xu CM ，Liu YX ，Wang XQ ，Zhang L ，Li M ，Zhu SW ，Xie ZJ ，Wang PH ，Duan LP ，Zhu HQ ... -  《-》