Kim Hye Won, Rhee Min Suk
Department of Biotechnology, College of Life Sciences and Biotechnology, Korea University, Seoul, South Korea.
Front Microbiol. 2018 Dec 21;9:3214. doi: 10.3389/fmicb.2018.03214. eCollection 2018.
As a foodborne and environmental pathogen, Shiga toxin-producing O157:H7 could pose a health threat to immunocompromised astronauts during a space mission. In this study, novel approaches, including real-time testing and direct evaluation of resistance mechanisms, were used to evaluate antibiotic efficacy against O157:H7 under low-shear modeled microgravity (LSMMG) produced using a rotary cell culture system. When compared with normal gravity (NG), bacterial growth was increased under LSMMG in the presence of sub-inhibitory nalidixic acid concentrations and there was an accompanying up-regulation of stress-related genes. LSMMG also induced transcriptional changes of the virulence genes and , highlighting the potential risk of inappropriate antibiotic use during a spaceflight. The degree of bacterial cell damage induced by the antibiotics was reduced under LSMMG, suggesting low induction of reactive oxygen species. Efflux pumps were also shown to play an important role in these responses. Increased cell filamentation was observed under LSMMG upon ampicillin treatment, possibly reflecting a protective mechanism against exposure to antibiotics. These observations indicate that, in the presence of antibiotics, the survival of O157:H7 is greater under LSMMG than under NG, indicating that antibiotic therapies may need to be adjusted during space missions.
作为一种食源性病原体和环境病原体，产志贺毒素的O157:H7在太空任务期间可能会对免疫功能低下的宇航员构成健康威胁。在本研究中，采用了包括实时检测和对耐药机制进行直接评估在内的新方法，以评估在使用旋转细胞培养系统产生的低剪切模拟微重力（LSMMG）条件下抗生素对O157:H7的疗效。与正常重力（NG）相比，在亚抑制浓度的萘啶酸存在下，LSMMG条件下细菌生长增加，且伴随有应激相关基因的上调。LSMMG还诱导了毒力基因和的转录变化，突出了太空飞行期间不适当使用抗生素的潜在风险。在LSMMG条件下，抗生素诱导的细菌细胞损伤程度降低，表明活性氧的诱导作用较低。外排泵在这些反应中也显示出重要作用。在氨苄青霉素处理下，LSMMG条件下观察到细胞丝状化增加，这可能反映了一种针对抗生素暴露的保护机制。这些观察结果表明，在存在抗生素的情况下，O157:H7在LSMMG条件下的存活率高于在NG条件下，这表明在太空任务期间可能需要调整抗生素治疗方法。
