Department of Gastroenterology, The Affiliated Hospital of Medical School, Ningbo University, Ningbo, China.
Institute of Environmental Medicine, Zhejiang University School of Medicine, Hangzhou, China.
Front Cell Infect Microbiol. 2021 Nov 16;11:711680. doi: 10.3389/fcimb.2021.711680. eCollection 2021.
It is believed that intestinal bacteria play an indispensable role in promoting intestinal inflammation. However, the characteristics of these tissue-associated bacteria remain elusive. The aim of this study is to explore the bacterial loads, compositions, and structures in the noninflamed mucosa, inflamed mucosa, and creeping fat taken from patients with Crohn's disease (CD).
Noninflamed mucosa, inflamed mucosa, and creeping fat samples were obtained from 10 surgical patients suffering from CD. Total bacterial DNA was extracted in a sterile environment using aseptic techniques. The V3-V4 regions of bacterial 16S rDNA were amplified and analysed using standard microbiological methods. qPCR was used to confirm the change in abundance of specific species in additional 30 independent samples.
Inflamed mucosa exhibited the highest bacterial load (3.8 and 12 times more than that of non-inflamed mucosa and creeping fat) and species diversity. The relative abundance of Proteobacteria was dominant in most samples and was negatively associated with Firmicutes. Moreover, the relative abundances of and in creeping fat significantly increased more than twice as much as other tissue types. The bacterial community structure analysis showed that the bacterial samples from the same individual clustered more closely.
This study reveals the significant differences in bacterial load, species diversity, and composition among different intestinal tissue types of CD patients and confirms that the bacterial samples from the same individual are highly correlated. Our findings will shed light on fully revealing the characteristics of tissue-associated bacteria and their roles in CD pathogenesis.
人们认为肠道细菌在促进肠道炎症中起着不可或缺的作用。然而，这些组织相关细菌的特征仍然难以捉摸。本研究旨在探索克罗恩病（CD）患者的非炎症性黏膜、炎症性黏膜和爬行脂肪中的细菌负荷、组成和结构。
从 10 名患有 CD 的手术患者中获取非炎症性黏膜、炎症性黏膜和爬行脂肪样本。使用无菌技术在无菌环境中提取总细菌 DNA。使用标准微生物学方法扩增和分析细菌 16S rDNA 的 V3-V4 区。qPCR 用于确认额外 30 个独立样本中特定物种丰度的变化。
炎症性黏膜表现出最高的细菌负荷（比非炎症性黏膜和爬行脂肪高 3.8 和 12 倍）和物种多样性。变形菌门的相对丰度在大多数样本中占主导地位，与厚壁菌门呈负相关。此外，爬行脂肪中的 和 的相对丰度显著增加了两倍以上，比其他组织类型增加得更多。细菌群落结构分析表明，来自同一个体的细菌样本聚类更紧密。
本研究揭示了 CD 患者不同肠道组织类型之间细菌负荷、物种多样性和组成的显著差异，并证实来自同一个体的细菌样本高度相关。我们的发现将有助于充分揭示组织相关细菌的特征及其在 CD 发病机制中的作用。
