PDF(Pubmed)
Abstract：
The bacterial pathogen Staphylococcus aureus harbors numerous virulence factors that impact infection severity. Beyond virulence gene presence or absence, the expression level of virulence proteins is known to vary across S. aureus lineages and isolates. However, the impact of expression level on severity is poorly understood due to the lack of high-throughput quantification methods of virulence proteins.
We present a targeted proteomic approach able to monitor 42 staphylococcal proteins in a single experiment. Using this approach, we compared the quantitative virulomes of 136 S. aureus isolates from a nationwide cohort of French patients with severe community-acquired staphylococcal pneumonia, all requiring intensive care. We used multivariable regression models adjusted for patient baseline health (Charlson comorbidity score) to identify the virulence factors whose in vitro expression level predicted pneumonia severity markers, namely leukopenia and hemoptysis, as well as patient survival.
We found that leukopenia was predicted by higher expression of HlgB, Nuc, and Tsst-1 and lower expression of BlaI and HlgC, while hemoptysis was predicted by higher expression of BlaZ and HlgB and lower expression of HlgC. Strikingly, mortality was independently predicted in a dose-dependent fashion by a single phage-encoded virulence factor, the Panton-Valentine leucocidin (PVL), both in logistic (OR 1.28; 95%CI[1.02;1.60]) and survival (HR 1.15; 95%CI[1.02;1.30]) regression models.
These findings demonstrate that the in vitro expression level of virulence factors can be correlated with infection severity using targeted proteomics, a method that may be adapted to other bacterial pathogens.
We present a targeted proteomic approach able to monitor 42 staphylococcal proteins in a single experiment. Using this approach, we compared the quantitative virulomes of 136 S. aureus isolates from a nationwide cohort of French patients with severe community-acquired staphylococcal pneumonia, all requiring intensive care. We used multivariable regression models adjusted for patient baseline health (Charlson comorbidity score) to identify the virulence factors whose in vitro expression level predicted pneumonia severity markers, namely leukopenia and hemoptysis, as well as patient survival.
We found that leukopenia was predicted by higher expression of HlgB, Nuc, and Tsst-1 and lower expression of BlaI and HlgC, while hemoptysis was predicted by higher expression of BlaZ and HlgB and lower expression of HlgC. Strikingly, mortality was independently predicted in a dose-dependent fashion by a single phage-encoded virulence factor, the Panton-Valentine leucocidin (PVL), both in logistic (OR 1.28; 95%CI[1.02;1.60]) and survival (HR 1.15; 95%CI[1.02;1.30]) regression models.
These findings demonstrate that the in vitro expression level of virulence factors can be correlated with infection severity using targeted proteomics, a method that may be adapted to other bacterial pathogens.
摘要：
细菌病原体金黄色葡萄球菌具有许多影响感染严重程度的毒力因子。超越毒力基因的存在或不存在，已知毒力蛋白的表达水平在金黄色葡萄球菌谱系和分离株中有所不同。然而,由于缺乏毒力蛋白的高通量定量方法,表达水平对严重程度的影响知之甚少.
我们提出了一种靶向蛋白质组学方法，能够在单个实验中监测42种葡萄球菌蛋白质。使用这种方法，我们比较了136株金黄色葡萄球菌分离株的定量病毒组，这些分离株来自法国全国范围内患有严重社区获得性葡萄球菌肺炎的患者，都需要重症监护.我们使用多变量回归模型调整患者基线健康（Charlson合并症评分），以确定其体外表达水平预测肺炎严重程度标志物的毒力因子。即白细胞减少和咯血，以及病人的生存。
我们发现白细胞减少是由HlgB的高表达预测的，Nuc,和Tsst-1以及BlaI和HlgC的较低表达，而咯血是通过BlaZ和HlgB的较高表达和HlgC的较低表达来预测的。引人注目的是，死亡率是通过单个噬菌体编码的毒力因子以剂量依赖性方式独立预测的，潘顿-瓦伦丁杀白素(PVL)，在logistic(OR1.28;95CI[1.02;1.60])和生存(HR1.15;95CI[1.02;1.30])回归模型中。
这些发现表明，使用靶向蛋白质组学，毒力因子的体外表达水平可以与感染严重程度相关。一种适用于其他细菌病原体的方法。
我们提出了一种靶向蛋白质组学方法，能够在单个实验中监测42种葡萄球菌蛋白质。使用这种方法，我们比较了136株金黄色葡萄球菌分离株的定量病毒组，这些分离株来自法国全国范围内患有严重社区获得性葡萄球菌肺炎的患者，都需要重症监护.我们使用多变量回归模型调整患者基线健康（Charlson合并症评分），以确定其体外表达水平预测肺炎严重程度标志物的毒力因子。即白细胞减少和咯血，以及病人的生存。
我们发现白细胞减少是由HlgB的高表达预测的，Nuc,和Tsst-1以及BlaI和HlgC的较低表达，而咯血是通过BlaZ和HlgB的较高表达和HlgC的较低表达来预测的。引人注目的是，死亡率是通过单个噬菌体编码的毒力因子以剂量依赖性方式独立预测的，潘顿-瓦伦丁杀白素(PVL)，在logistic(OR1.28;95CI[1.02;1.60])和生存(HR1.15;95CI[1.02;1.30])回归模型中。
这些发现表明，使用靶向蛋白质组学，毒力因子的体外表达水平可以与感染严重程度相关。一种适用于其他细菌病原体的方法。
