Strains of the bacterium Enterobacter, similar to newly found opportunistic infectious organisms seen in a few hospital settings, have been identified on the International Space Station (ISS). The strains found in space were not pathogenic to humans, but researchers believe they should be studied for potential health implications for future missions, according to a study published in the open access journal BMC Microbiology.
Researchers at the Jet Propulsion Laboratory, California Institute of Technology, USA investigated five strains of Enterobacter that were isolated from the space toilet and the exercise platform on the ISS in March 2015 as part of a wider effort to characterize the bacterial communities that live on surfaces inside the space station. To identify the species of Enterobacter collected on the ISS and to show in detail the genetic make-up of the individual strains, the researchers compared the ISS strains to all publicly available genomes of 1,291 Enterobacter strains collected on Earth.
Dr Kasthuri Venkateswaran, Senior Research Scientist at the Jet Propulsion Laboratory Biotechnology and Planetary Protection Group and the corresponding author of the study said: “To show which species of the bacteria were present on the ISS, we used various methods to characterize their genomes in detail. We revealed that genomes of the five ISS Enterobacter strains were genetically most similar to three strains newly found on Earth. These three strains belonged to one species of the bacteria, called Enterobacter bugandensis, which had been found to cause disease in neonates and a compromised patient, who were admitted to three different hospitals (in east Africa, Washington state and Colorado).”
喷气推进实验室生物技术和行星保护小组的高级研究科学家Kasthuri Venkateswaran博士说：“为了鉴别出国际空间站上的细菌是哪些品种，我们使用了多种办法来详细鉴定它们的基因组。我们发现5种国际空间内的肠杆菌菌株与新近在地球上发现的3种菌株在基因组成上最为相似。这3种菌株均属同一品种的细菌Enterobacter bugandensis，这种细菌会导致新生儿和缺乏抵抗力的病人患病，病例曾出现在3个不同的医院（分别位于东非、华盛顿州和科罗拉多州）。”
Comparing the genomes of the five ISS strains to the three clinical Earth strains allowed the authors to get a better understanding of whether the ISS strains showed characteristics of antimicrobial resistance, if they had gene profiles similar to those found in known multi-drug resistant bacteria, and to identify genes related to their ability to cause disease (pathogenic potential).
Dr. Nitin Singh, first author of the publication said: “Given the multi-drug resistance results for these ISS E. bugandensis genomes and the increased chance of pathogenicity we have identified, these species potentially pose important health considerations for future missions. However, it is important to understand that the strains found on the ISS were not virulent, which means they are not an active threat to human health, but something to be monitored.”
研究的第一作者Nitin Singh博士说：“鉴于这些空间站的E. bugandensis细菌的基因组中发现的多药耐药性结果和我们已经确认的致病性升高的概率，这些细菌可能对未来的任务有重要的健康影响。不过很重要的一点是，在国际空间站上发现的细菌菌株都是无毒的，这意味着它们不会给人类健康带来主动威胁，但应该被监测起来。”
The authors found that the ISS isolates had similar antimicrobial resistance patterns to the three clinical strains found on Earth and that they included 112 genes involved in virulence, disease and defense. While the ISS E. bugandensis strains were not pathogenic to humans, the authors predicted via computer analyses, a 79% probability that they may potentially cause disease. However, analyses in living organisms should be carried out to confirm this.
Dr Venkateswaran said: “Whether or not an opportunistic pathogen like E. bugandensis causes disease and how much of a threat it is, depends on a variety of factors, including environmental ones. Further in vivo studies are needed to discern the impact that conditions on the ISS, such as microgravity, other space, and spacecraft-related factors, may have on pathogenicity and virulence.”
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Notes to editor附注:
1. Research article原文:
Multi-drug resistant Enterobacter bugandensis species isolated from the International Space Station and comparative genomic analyses with human pathogenic strains
BMC Microbiology 2018
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2. BMC Microbiology is an open access, peer-reviewed journal that considers articles on analytical and functional studies of prokaryotic and eukaryotic microorganisms, viruses and small parasites, as well as host and therapeutic responses to them and their interaction with the environment.
3. A pioneer of open access publishing, BMC has an evolving portfolio of high quality peer-reviewed journals including broad interest titles such as BMC Biology and BMC Medicine, specialist journals such as Malaria Journal and Microbiome, and the BMC series. At BMC, research is always in progress. We are committed to continual innovation to better support the needs of our communities, ensuring the integrity of the research we publish, and championing the benefits of open research. BMC is part of Springer Nature, giving us greater opportunities to help authors connect and advance discoveries across the world.
BMC作为开放获取出版的先锋，不断推出一系列高质量的同行评议期刊，这包括了BMC Biology 和BMC Medicine等涵盖范围较广的期刊，以及Malaria Journal、Microbiome和BMC系列期刊等专门刊物。BMC认为，科研永不止步。因此，我们致力于不断创新，以更好地满足科学共同体的需要，确保所发表的科研成果的完整性，并推广开放研究的益处。BMC是施普林格∙自然旗下机构，这让我们更有机会帮助世界各地的作者相互沟通并促进科学发现。