School of Life Science, Beijing Institute of Technology, Beijing, 100081, China.
Institute of Manned Space System Engineering, China Academy of Space Technology, Beijing, 100094, China.
Microb Ecol. 2019 Oct;78(3):631-650. doi: 10.1007/s00248-019-01344-4. Epub 2019 Feb 26.
Sufficient evidence indicates that orbiting space stations contain diverse microbial populations, which may threaten astronaut health and equipment reliability. Understanding the composition of microbial communities in space stations will facilitate further development of targeted biological safety prevention and maintenance practices. Therefore, this study systematically investigated the microbial community of China's Space Station (CSS). Air and surface samples from 46 sites on the CSS and Assembly Integration and Test (AIT) center were collected, from which 40 bacteria strains were isolated and identified. Most isolates were cold- and desiccation-resistant and adapted to oligotrophic conditions. Bacillus was the dominant bacterial genus detected by both cultivation-based and Illumina MiSeq amplicon sequencing methods. Microbial contamination on the CSS was correlated with encapsulation staff activities. Analysis by spread plate and qPCR revealed that the CSS surface contained 2.24 × 10-5.47 × 10 CFU/100 cm culturable bacteria and 9.32 × 10-5.64 × 10 16S rRNA gene copies/100cm; BacLight™ analysis revealed that the viable/total bacterial cell ratio was 1.98-13.28%. This is the first study to provide important systematic insights into the microbiome of the CSS during assembly that describes the pre-launch microbial diversity of the space station. Our findings revealed the following. (1) Bacillus strains and staff activities should be considered major concerns for future biological safety. (2) Autotrophic and multi-resistant microbial communities were widespread in the AIT environment. Although harsh cleaning methods reduced the number of microorganisms, stress-resistant strains were not completely removed. (3) Sampling, storage and analytical methods for the space station were thoroughly optimized, and are expected to be applicable to low-biomass environments in general. Microbiology-related future works will follow up to comprehensively understand the changing characteristics of microbial communities in CSS.
有充分的证据表明，轨道空间站含有多种微生物种群，这可能会威胁到宇航员的健康和设备的可靠性。了解空间站微生物群落的组成将有助于进一步制定有针对性的生物安全预防和维护措施。因此，本研究系统地调查了中国空间站（CSS）的微生物群落。从 CSS 和总装集成测试（AIT）中心的 46 个地点采集了空气和表面样本，从中分离和鉴定了 40 株细菌。大多数分离株具有耐冷和干燥的特性，并适应贫营养条件。通过培养和 Illumina MiSeq 扩增子测序两种方法检测到的优势细菌属均为芽孢杆菌属。CSS 上的微生物污染与封装人员的活动有关。平板计数和 qPCR 分析表明，CSS 表面含有 2.24×10-5.47×10 CFU/100 cm 可培养细菌和 9.32×10-5.64×10 16S rRNA 基因拷贝/100 cm；BacLight™分析表明，活/总细菌细胞比为 1.98-13.28%。这是第一项在组装过程中对 CSS 微生物组进行的重要系统研究，描述了空间站的发射前微生物多样性。我们的研究结果揭示了以下几点。（1）芽孢杆菌菌株和人员活动应被视为未来生物安全的主要关注点。（2）AIT 环境中广泛存在自养和多抗性微生物群落。虽然苛刻的清洁方法减少了微生物的数量，但压力抗性菌株并未完全去除。（3）空间站的采样、储存和分析方法得到了彻底优化，预计将适用于一般低生物量环境。未来的微生物学相关工作将跟进，以全面了解 CSS 中微生物群落的变化特征。
