Blachowicz Adriana, Urbaniak Camilla, Adolphson Alec, Isenhouer Gwyn, Page Andy, Venkateswaran Kasthuri
Biotechnology and Planetary Protection Group, Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109, USA.
ZIN Technologies Inc., Middleburg Heights, OH 44130, USA.
Microorganisms. 2023 Sep 13;11(9):2310. doi: 10.3390/microorganisms11092310.
The pressing need to safeguard the health of astronauts aboard the International Space Station (ISS) necessitates constant and rigorous microbial monitoring. Recognizing the shortcomings of traditional culture-based methods, NASA is deliberating the incorporation of molecular-based techniques. The challenge, however, lies in developing and validating effective methods for concentrating samples to facilitate this transition. This study is dedicated to investigating the potential of an ISS Smart Sample Concentrator (iSSC) as an innovative concentration method. First, the iSSC system and its components were tested and optimized for microgravity, including various testing environments: a drop tower, parabolic flight, and the ISS itself. Upon confirming the system's compatibility with microgravity, we further evaluated its proficiency and reliability in concentrating large volumes (i.e., 1 L) of water samples inoculated with different microbes. The samples carried 10 to 10 colony-forming units (CFUs) of , , or per liter, aligning with NASA's acceptable limit of 5 × 10 CFU/L. The average retrieved volume post-concentration was ≈450 µL, yielding samples that were ≈2200 times more concentrated for subsequent quantitative PCR (qPCR) and CFU analysis. The average microbial percent recovery, as assessed with CFU counts, demonstrated consistency for and at around 50% and 45%, respectively. For , the efficiency oscillated between 40% and 80%. Interestingly, when we examined microbial recovery using qPCR, the results showed more variability across all tested species. The significance of these findings lies not merely in the successful validation of the iSSC but also in the system's proven consistency, as evidenced by its alignment with previous validation-phase results. In conclusion, conducted research underscored the potential of the iSSC in monitoring microbial contamination in potable water aboard the ISS, heralding a paradigm shift from culture-based to molecular-based monitoring methods.
保障国际空间站（ISS）上宇航员的健康这一紧迫需求使得持续且严格的微生物监测成为必要。鉴于传统基于培养的方法存在缺陷，美国国家航空航天局（NASA）正在考虑采用基于分子的技术。然而，挑战在于开发并验证有效的样品浓缩方法以推动这一转变。本研究致力于探究国际空间站智能样品浓缩器（iSSC）作为一种创新浓缩方法的潜力。首先，对iSSC系统及其组件进行了微重力测试和优化，测试环境包括落塔、抛物线飞行以及国际空间站本身。在确认该系统与微重力兼容后，我们进一步评估了其在浓缩接种了不同微生物的大量（即1升）水样方面的能力和可靠性。这些样品每升含有10至10个 、 或 的菌落形成单位（CFU），符合NASA可接受的5×10 CFU/L的限值。浓缩后的平均回收体积约为450微升，得到的样品浓缩了约2200倍，用于后续的定量聚合酶链反应（qPCR）和CFU分析。通过CFU计数评估的平均微生物回收率显示， 和 的回收率分别在50%和45%左右保持一致。对于 ，效率在40%至80%之间波动。有趣的是，当我们使用qPCR检测微生物回收率时，结果显示在所有测试物种中变异性更大。这些发现的意义不仅在于iSSC的成功验证，还在于该系统已证明的一致性，这与先前验证阶段的结果相符。总之，所开展的研究强调了iSSC在监测国际空间站饮用水中微生物污染方面的潜力，预示着从基于培养的监测方法向基于分子的监测方法的范式转变。
