Effects of prolonged exposure to moderate static magnetic field and its synergistic effects with alkaline pH on Enterococcus faecalis
Effects of prolonged exposure to moderate static magnetic field and its synergistic effects with alkaline pH on Enterococcus faecalis
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长时间暴露于中等静磁场及其与碱性pH值的协同作用对粪肠球菌的影响
DOI：
10.1016/j.micpath.2017.12.028
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发表时间：
2018-02-01
影响因子：
3.8
通讯作者：
Fan, Bing
中科院分区：
文献类型：
--
作者：
Fan, Wei;Huang, Zhuo;Fan, Bing
静电磁场（SMF）已被证明对多种微生物具有生物学影响，但其对粪肠球菌的影响尚未见报道，粪肠球菌与多种牙齿感染有关。此外，粪肠球菌被发现对一种主要的牙科抗菌剂氢氧化钙提供的碱性环境具有抗性。因此，本研究评估了长期暴露于中等SMF （170 mT）的抗菌活性及其与碱性pH （pH = 9）可能的协同活性。在这些条件下形成生物膜的能力用结晶紫法检测。实时荧光定量PCR检测应激相关基因（dnaK和groEL）和毒力相关基因（efaA、ace、gelE和fsrC）的相对表达量。结果表明，SMF作用120 h后，细胞增殖受到抑制。此外，SMF与碱性pH联合处理的抗菌效果显著高于单一SMF和碱性pH处理24 h和72 h。然而，在SMF和碱性pH处理下，形成生物膜的能力也增强了。SMF通过上调dnaK的表达诱导应激反应，提高毒力基因（efaA和ace）的表达。当同时暴露于SMF和碱性pH时，这些反应更为显著，包括groEL、gelE和fsrC在内的更多基因上调。因此，SMF与碱性pH的组合可能是一种很有前途的消毒策略，用于牙齿区域和其他与粪肠球菌感染相关的区域。
Static magnetic field (SMF) has been shown to biologically affect various microorganisms, but its effects on Enterococcus faecalis, which is associated with multiple dental infections, have not been reported yet. Besides, Enterococcus faecalis was found to be resistant to the alkaline environment provided by a major dental antimicrobial, calcium hydroxide. Therefore, the antibacterial activity of prolonged exposure to moderate SMF (170 mT) and its possible synergistic activity with alkaline pH (pH = 9) were evaluated in the study. The ability to form a biofilm under these conditions was examined by crystal violet assay. Real-time quantitative PCR was performed to evaluate the relative expression of stress (dnaK and groEL) and virulence (efaA, ace, gelE and fsrC) related genes. As the results indicated, cell proliferation was inhibited after 120 h of SMF exposure. What's more, the combined treatment of SMF and alkaline pH showed significantly improved antimicrobial action when compared to single SMF and alkaline pH treatment for more than 24 h and 72 h respectively. However, the ability to form a biofilm was also enhanced under SMF and alkaline pH treatments. SMF can induce stress response by up-regulating the expression of dnaK and elevate virulence gene expression (efaA and ace). These responses were more significant and more genes were up-regulated including groEL, gelE and fsrC when exposed to SMF and alkaline pH simultaneously. Hence, combination of SMF and alkaline pH could be a promising disinfection strategy in dental area and other areas associated with Enterococcus faecalis infections.