Table_2_Temporal Characteristics of the Oropharyngeal and Nasal Microbiota Structure in Crewmembers Stayed 180 Days in the Controlled Ecological Life Support System.XLSX

Confined experiments are carried out to simulate the closed environment of space capsule on the ground. The Chinese Controlled Ecological Life Support System (CELSS) is designed including a closed-loop system supporting 4 healthy volunteers surviving for 180 days, and we aim to reveal the temporal characteristics of the oropharyngeal and nasal microbiota structure in crewmembers stayed 180 days in the CELSS, so as to accumulate the information about microbiota balance associated with respiratory health for estimating health risk in future spaceflight. We investigated the distribution of microorganisms and their dynamic characteristics in the nasal cavity and oropharynx of occupants with prolonged confinement. Based on the 16S rDNA v3–v4 regions using Illumina high-throughput sequencing technology, the oropharyngeal and nasal microbiota were monitored at eight time points during confinement. There were significant differences between oropharyngeal and nasal microbiota, and there were also individual differences among the same site of different volunteers. Analysis on the structure of the microbiota showed that, in the phylum taxon, the nasal bacteria mainly belonged to Actinobacteria, Firmicutes, Proteobacteria, Bacteroidetes, etc. In addition to the above phyla, in oropharyngeal bacteria Fusobacterial accounted for a relatively high proportion. In the genus taxon, the nasal and oropharyngeal bacteria were independent. Corynebacterium and Staphylococcus were dominant in nasal cavity, and Corynebacterium, Streptococcus, and Neisseria were dominant in oropharynx. With the extension of the confinement time, the abundance of Staphylococcus in the nasal cavity and Neisseria in the oropharynx increased, and the index Chao fluctuated greatly from 30 to 90 days after the volunteers entered the CELSS.
Conclusion: The structure and diversity of the nasal and oropharyngeal microbiota changed in the CELSS, and there was the phenomenon of migration between occupants, suggesting that the microbiota structure and health of the respiratory tract could be affected by living in a closed environment for a long time.

本研究于地面开展密闭实验，以模拟太空舱的封闭环境。所构建的中国受控生态生保系统（Chinese Controlled Ecological Life Support System, CELSS）包含可支持4名健康志愿者生存180天的闭环系统，本研究旨在揭示在该系统中驻留180天的乘员口咽与鼻腔菌群结构的时间特征，以期积累与呼吸道健康相关的菌群平衡数据，用于评估未来航天任务的健康风险。
本研究针对长期密闭居住的乘员鼻腔及口咽部微生物的分布与动态特征展开调查。基于16S rDNA v3–v4可变区，采用Illumina高通量测序技术，在密闭实验期间的8个时间点对乘员口咽及鼻腔菌群进行监测。研究发现，口咽部与鼻腔菌群间存在显著差异，不同志愿者的同一采样部位菌群也存在个体差异。
菌群结构分析显示，在门水平分类群中，鼻腔菌群主要隶属于放线菌门（Actinobacteria）、厚壁菌门（Firmicutes）、变形菌门（Proteobacteria）、拟杆菌门（Bacteroidetes）等；除上述菌门外，口咽部菌群中梭杆菌门（Fusobacteriota）的相对丰度较高。在属水平分类群中，鼻腔与口咽部菌群组成各具特征：鼻腔菌群以棒状杆菌属（Corynebacterium）和葡萄球菌属（Staphylococcus）为主，口咽部菌群则以棒状杆菌属、链球菌属（Streptococcus）和奈瑟菌属（Neisseria）为主。随着密闭实验时长的延长，鼻腔内葡萄球菌属的丰度以及口咽部奈瑟菌属的丰度均呈上升趋势；志愿者进入系统后30至90天内，Chao多样性指数波动幅度较大。
研究结论：密闭环境下乘员鼻腔与口咽部菌群的结构及多样性发生改变，且存在乘员间菌群迁移现象，提示长期处于封闭环境可对呼吸道菌群结构及呼吸道健康产生影响。