文章：Early life establishment of site-specific microbialcommunities in the gut

杂志：Gut Microbes  2014

   研究目的：To assess the stratification of microbes in the newborn gut and to evaluate the probable shortcoming of fecalsampling in place of tissue sampling 比较新生儿肠道不同部位的菌群分布情况，以及用粪便中菌群作为肠道菌群代替的缺陷。

   研究结论：First, when the site of fecal and mucosal samples are further apart, their microbial communities are more distinct, as indicated by low mean Sørensen similarity indices for each patient’s fecal and tissue microbiota. 大肠和粪便菌群存在较大区别。Second, two distinct niches (intestinal mucosa and fecal microbiota)are evident by principal component analyses, demonstrating the critical role of sample source in defining microbial composition. PCoA发现大肠和粪便是两个不同类别。Finally, in contrast to adult studies, intestinal bacterial diversity was higher in tissue than in fecal samples. 多样性存在差异。

   研究方案：Fifteen neonates (8 females, 7 males) undergoing intestinal resections were recruited for this study. Eight patients were exposed to antibiotics at least 24 h prior to surgery. The majority of tissue samples were obtained from the small intestine (10 ileal and 3 jejunal samples); two colonic samples were also collected. 选择 15个新生儿样本，8个女孩，7个男孩，都是在进行intestinal resections，15个样品的取样部位存在细微区别，详细如下

    研究结论：

   1）SI指数的区别，SI表示样品的相关性。SI is a statistic that compares the similarity of two samples, with exact similarity of the feces and tissue microbiota set at 1 and no similarity set at 0. 如上表所示，最大值为0.52。

  2）CN指数的区别，CN是表示相似型。We observed the same trend when we used the Sorensen Quantitative index (CN) with 95% Bootstrap confidence intervals, a similarity metric that compares the similarity of two samples on the basis of taxon presence or absence。相似度也不是很高。

   3）大肠和粪便的数据在聚类模式上基本不同

   4）比较主要几个门在大肠和粪便中的含量分布，如下图所示，含量存在明显差异

   5）PCoA分析后发现，大肠和粪便分布在2个不同的类

   6）Simpson’s inverse index, Shannon-Wiener和Chao 1值在大肠、粪便中的差异

   在当前的研究中，不能简单用粪便代替肠道菌群。

   此文的研究中，选取的样本是一些患有疾病的样本，缺乏健康的样本。

   样品具体是新生儿的样品，且粪便是胎粪样品。（婴儿不同时间，粪便中菌群分布是不同的）

   取样的时间聚焦在一个点上，没有扩大时间维度的取样。

   SI指数可以借鉴用来表示样品的相似性。