Environmental Science Graduate Program, The Ohio State University, Columbus, OH, 43210, USA.
Department of Civil, Environmental & Geodetic Engineering, College of Engineering, Environmental Health Sciences, The Ohio State University, 470 Hitchcock Hall, 2070 Neil Ave, Columbus, OH, 43210, USA.
Appl Microbiol Biotechnol. 2019 Sep;103(18):7767-7782. doi: 10.1007/s00253-019-10053-4. Epub 2019 Aug 6.
Exposure to bioaerosols can adversely influence human health through respiratory tract, eye, and skin irritation. Bioaerosol composition is unique on the International Space Station (ISS), where the size distribution of particles in the air differs from those on Earth. This is due to the lack of gravitational settling and sources of biological particles. However, we do not understand how microbes are influenced by particle size in this environment. We analyzed two types of samples from the ISS: (1) vacuum bag debris which had been sieved into five different size fractions and (2) passively collected particles on a tape substrate with a passive aerosol sampler. Using quantitative polymerase chain reaction (qPCR), the highest concentration of fungal spores was found in the 106-150 μm-sized sieved dust particles, while the highest concentration of bacterial cells was found in the 150-250 μm-sized sieved dust particles. Illumina MiSeq DNA sequencing revealed that particle size was associated with bacterial and fungal communities and statistically significant (p = 0.035, p = 0.036 respectively). Similar fungal and bacterial species were found within the passive aerosol sample and the sieved dust samples. The most abundant fungal species identified in the aerosol and sieved samples are commonly found in food and plant material. Abundant bacterial species were most associated with the oral microbiome and human upper respiratory tract. One limitation to this study was the suboptimal storage conditions of the sieved samples prior to analysis. Overall, our results indicate that microbial exposure in space may depend on particle size. This has implications for ventilation and filtration system design for future space vehicles and habitats.
生物气溶胶的暴露会通过呼吸道、眼睛和皮肤刺激对人体健康产生不利影响。国际空间站（ISS）上的生物气溶胶组成是独特的，空气中颗粒的大小分布与地球上的不同。这是由于缺乏重力沉降和生物颗粒的来源。然而，我们并不了解在这种环境中微生物如何受到颗粒大小的影响。我们分析了来自 ISS 的两种类型的样本：（1）已经过筛分至五个不同大小级别的真空袋碎片，以及（2）使用被动气溶胶采样器在胶带基质上被动收集的颗粒。使用定量聚合酶链反应（qPCR），发现真菌孢子的浓度最高的是 106-150μm 大小的筛分尘埃颗粒，而细菌细胞的浓度最高的是 150-250μm 大小的筛分尘埃颗粒。Illumina MiSeq DNA 测序表明，颗粒大小与细菌和真菌群落有关，且具有统计学意义（p = 0.035，p = 0.036）。在被动气溶胶样本和筛分尘埃样本中都发现了相似的真菌和细菌种类。在气溶胶和筛分样本中鉴定出的最丰富的真菌种类通常存在于食物和植物材料中。最丰富的细菌种类与口腔微生物组和人体上呼吸道最相关。本研究的一个局限性是在分析之前，对筛分样本的储存条件不理想。总的来说，我们的结果表明，空间中的微生物暴露可能取决于颗粒大小。这对未来太空飞行器和栖息地的通风和过滤系统设计有影响。
