Liu Daohong, Li Zhirui, Wang Guoqi, Li Tongtong, Zhang Lihai, Tang Peifu
Department of Orthopedics, The 309th Hospital of PLA, Beijing, 100091, China.
Department of Orthopedics, The General Hospital of People's Liberation Army, Beijing, 100853, China.
Antonie Van Leeuwenhoek. 2018 Feb;111(2):161-170. doi: 10.1007/s10482-017-0938-z. Epub 2017 Sep 11.
The aim of this study was to evaluate the virulence of Staphylococcus aureus in a controlled animal study using the standard sterile gauze and negative pressure wound therapy (NPWT), including activation of agr, gene expression and production of virulence foctors and depth of bacterial invasion. The tissue specimens were harvested on days 0 (6 h after bacterial inoculation), 2, 4, 6, and 8 at the center of wound beds. Laser scanning confocal microscopy was performed to obtain bioluminescent images which were used to measure the depth of bacterial invasion. The agrA expression of S.aureus and the transcription and production of virulence factors including Eap, Spa and α-toxin were significantly different. The bacterial invasion depth was significantly less with effect of NPWT. The markedly different activation of quorum sensing systems that enable cell-to-cell communication and regulation of numerous colonization and virulence factors result in distinct gene expression and pathogenicity over time in different microenvironment. Thus, the agr system represents a fundamental regulatory paradigm that can encompass different adaptive strategies and accommodate horizontally acquired virulence determinants.
本研究的目的是在一项对照动物研究中，使用标准无菌纱布和负压伤口治疗（NPWT）评估金黄色葡萄球菌的毒力，包括agr的激活、基因表达、毒力因子的产生以及细菌入侵深度。在第0天（细菌接种后6小时）、第2天、第4天、第6天和第8天，在伤口床中心采集组织标本。进行激光扫描共聚焦显微镜检查以获得用于测量细菌入侵深度的生物发光图像。金黄色葡萄球菌的agrA表达以及包括Eap、Spa和α-毒素在内的毒力因子的转录和产生存在显著差异。NPWT的作用使细菌入侵深度显著降低。群体感应系统的明显不同激活能够实现细胞间通讯并调节众多定植和毒力因子，随着时间推移，在不同微环境中导致不同的基因表达和致病性。因此，agr系统代表了一种基本的调控模式，它可以涵盖不同的适应性策略并容纳水平获得的毒力决定因素。
