Composition and consistence of the bacterial microbiome in upper, middle and lower esophagus before and after Lugol’s iodine staining in the esophagus cancer screening

Esophageal bacteria, as the integral composition of human ecosystem, have been reported to be associated with esophageal lesions. However, few studies focus on microbial compositions in different esophageal segments, especially after Lugol’s iodine staining (LIS) in the endoscopic examination for the screening of esophageal cancer. We aim to investigate the composition of the bacterial microbiome in upper, middle and lower esophagus and if LIS would affect the detection of bacteria. A total of 141 fasting samples including the upper, middle and lower esophagus from 27 participants were collected by brushing the mucosal surface of the esophagus before (Eso) and after (Lug) LIS. Bacterial V3–V4 region of 16S rRNA gene was amplified and sequenced by Illumina’s sequencing platform. The top six abundant bacterial phyla taxa among three locations from both Eso and Lug groups were Proteobacteria, Firmicutes, Bacteroidetes, Actinobacteria, Fusobacteria and TM7. In terms of genera, the bacterium in three locations from two groups was all characterized by a highest relative abundance of <i>Streptococcus</i>. Bacteria diversity and the relative abundance between Eso and Lug were comparable (<i>p</i> &gt; .05). Bacteria diversity was consistent in different esophageal locations within the individual. The bacterial microbiome in healthy esophagus are highly diverse and consistent even among three physiological sites at all clades. Lugol’s iodine staining would not change local microenvironment in term of microbial composition. These findings provide an essential baseline for future studies investigating local and systemic bacterial microbiome and esophageal diseases.

食管菌群作为人体微生态系统的核心组成部分，已有研究证实其与食管病变密切相关。然而目前鲜有研究关注不同食管节段的菌群组成，尤其是在食管癌筛查的内镜检查中实施卢戈碘染色（Lugol’s iodine staining, LIS）后的菌群特征。本研究旨在探究食管上段、中段及下段的细菌菌群组成，并明确卢戈碘染色是否会影响细菌检测结果。本研究共纳入27名受试者，通过刷取食管黏膜表面，分别采集卢戈碘染色前（Eso）及染色后（Lug）的食管上段、中段、下段样本，总计141份空腹样本。采用Illumina测序平台对16S rRNA基因的细菌V3–V4可变区进行扩增及高通量测序。在染色前、后两组的三个食管节段中，丰度排名前六的细菌菌门依次为变形菌门（Proteobacteria）、厚壁菌门（Firmicutes）、拟杆菌门（Bacteroidetes）、放线菌门（Actinobacteria）、梭杆菌门（Fusobacteria）及TM7菌门（TM7）。在菌属水平上，两组的三个食管节段中，丰度最高的细菌均为*链球菌属（Streptococcus）*。染色前、后两组的菌群多样性及物种相对丰度均无统计学显著差异（p>0.05）。同一受试者体内不同食管节段的菌群多样性保持一致。健康人体食管的细菌菌群具有高度多样性，且在三个生理节段的所有进化枝中均保持一致。卢戈碘染色不会改变食管局部的菌群组成相关微环境。本研究结果为后续探究局部及全身细菌菌群与食管疾病的关联研究提供了重要的基准参考。