Staphylococcus aureus colonizes the nares of approximately 30% of humans, a risk factor for opportunistic infections. To gain insight into S. aureus virulence potential in the spaceflight environment, we analyzed RNA-Seq, cellular proteomics, and metabolomics data from the “Biological Research in Canisters-23” (BRIC-23) GeneLab spaceflight experiment, a mission designed to measure the response of S. aureus to growth in low earth orbit on the international space station. This experiment used Biological Research in Canisters-Petri Dish Fixation Units (BRIC-PDFUs) to grow asynchronous ground control and spaceflight cultures of S. aureus for 48 h. RNAIII, the effector of the Accessory Gene Regulator (Agr) quorum sensing system, was the most highly upregulated gene transcript in spaceflight relative to ground controls. The agr operon gene transcripts were also highly upregulated during spaceflight, followed by genes encoding phenol-soluble modulins and secreted proteases, which are positively regulated by Agr. Upregulated spaceflight genes/proteins also had functions related to urease activity, type VII-like Ess secretion, and copper transport. We also performed secretome analysis of BRIC-23 culture supernatants, which revealed that spaceflight samples had increased abundance of secreted virulence factors, including Agr-regulated proteases (SspA, SspB), staphylococcal nuclease (Nuc), and EsxA (secreted by the Ess system). These data also indicated that S. aureus metabolism is altered in spaceflight conditions relative to the ground controls. Collectively, these data suggest that S. aureus experiences increased quorum sensing and altered expression of virulence factors in response to the spaceflight environment that may impact its pathogenic potential.

金黄色葡萄球菌寄生在大约 30% 的人的鼻孔中，这是机会性感染的危险因素。为了深入了解金黄色葡萄球菌在航天环境中的毒力潜力，我们分析了来自“Canisters-23 生物学研究”(BRIC-23) GeneLab 航天实验的 RNA 测序、细胞蛋白质组学和代谢组学数据，该任务旨在测量金黄色葡萄球菌对国际空间站近地轨道生长的反应。该实验使用罐培养皿固定装置中的生物研究 (BRIC-PDFU) 来培养金黄色葡萄球菌的异步地面控制和航天培养物48 小时。RNAIII 是辅助基因调节器 (Agr) 群体感应系统的效应子，是太空飞行中相对于地面对照上调程度最高的基因转录本。agr操纵子基因转录本在太空飞行期间也高度上调，其次是编码酚溶性调节蛋白和分泌蛋白酶的基因，这些基因受到Agr的正向调节。上调的航天基因/蛋白质还具有与脲酶活性、VII型Ess分泌和铜转运相关的功能。我们还对 BRIC-23 培养物上清液进行了分泌组分析，结果表明航天样本中分泌毒力因子的丰度有所增加，包括 Agr 调节的蛋白酶（SspA、SspB）、葡萄球菌核酸酶（Nuc）和 EsxA（由 Ess 系统分泌） ）。这些数据还表明，相对于地面对照，金黄色葡萄球菌的代谢在太空飞行条件下发生了改变。总的来说，这些数据表明，金黄色葡萄球菌群体感应增强，毒力因子表达改变，以应对可能影响其致病潜力的太空飞行环境。