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.

Background: 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.

Methods: 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.

Results: 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 . Bacteria diversity and the relative abundance between Eso and Lug were comparable ( > .05). Bacteria diversity was consistent in different esophageal locations within the individual.

Conclusion: 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.