Abstract：
BACKGROUND: Raman microscopic spectroscopyis a new approach for further characterization and detection of molecular features in many pathological processes. This technique has been successfully applied to scrutinize the spatial distribution of small molecules and proteins within biological systems by in situ analysis. This study uses Raman microscopic spectroscopyto identify any in-depth benefits and drawbacks in diagnosing Staphylococcus epidermidis in human bone grafts.
METHODS: 40 non-infected human bone samples and 10 human bone samples infected with Staphylococcus epidermidis were analyzed using Raman microscopic spectroscopy. Reflectance data were collected between 200 cm-1 and 3600 cm-1 with a spectral resolution of 4 cm-1 using a Senterra II microscope (Bruker, Ettlingen, Germany). The acquired spectral information was used for spectral and unsupervised classification, such as principal component analysis.
RESULTS: Raman measurements produced distinct diagnostic spectra that were used to distinguish between non-infected human bone samples and Staphylococcus epidermidis infected human bone samples by spectral and principal component analyses. A substantial loss in bone quality and protein conformation was detected by human bone samples co-cultured with Staphylococcus epidermidis. The mineral-to-matrix ratio using the phosphate/Amide I ratio (p = 0.030) and carbonate/phosphate ratio (p = 0.001) indicates that the loss of relative mineral content in bones upon bacterial infection is higher than in non-infected human bones. Also, an increase of alterations in the collagen network (p = 0.048) and a decrease in the structural organization and relative collagen in infected human bone could be detected. Subsequent principal component analyses identified Staphylococcus epidermidis in different spectral regions, respectively, originating mainly from CH2 deformation (wagging) of protein (at 1450 cm-1) and bending and stretching modes of C-H groups (∼2800-3000 cm-1).
CONCLUSIONS: Raman microscopic spectroscopyis presented as a promising diagnostic tool to detect Staphylococcus epidermidis in human bone grafts. Further studies in human tissues are warranted.
METHODS: 40 non-infected human bone samples and 10 human bone samples infected with Staphylococcus epidermidis were analyzed using Raman microscopic spectroscopy. Reflectance data were collected between 200 cm-1 and 3600 cm-1 with a spectral resolution of 4 cm-1 using a Senterra II microscope (Bruker, Ettlingen, Germany). The acquired spectral information was used for spectral and unsupervised classification, such as principal component analysis.
RESULTS: Raman measurements produced distinct diagnostic spectra that were used to distinguish between non-infected human bone samples and Staphylococcus epidermidis infected human bone samples by spectral and principal component analyses. A substantial loss in bone quality and protein conformation was detected by human bone samples co-cultured with Staphylococcus epidermidis. The mineral-to-matrix ratio using the phosphate/Amide I ratio (p = 0.030) and carbonate/phosphate ratio (p = 0.001) indicates that the loss of relative mineral content in bones upon bacterial infection is higher than in non-infected human bones. Also, an increase of alterations in the collagen network (p = 0.048) and a decrease in the structural organization and relative collagen in infected human bone could be detected. Subsequent principal component analyses identified Staphylococcus epidermidis in different spectral regions, respectively, originating mainly from CH2 deformation (wagging) of protein (at 1450 cm-1) and bending and stretching modes of C-H groups (∼2800-3000 cm-1).
CONCLUSIONS: Raman microscopic spectroscopyis presented as a promising diagnostic tool to detect Staphylococcus epidermidis in human bone grafts. Further studies in human tissues are warranted.
摘要：
背景：拉曼显微光谱法是一种用于进一步表征和检测许多病理过程中分子特征的新方法。该技术已成功应用于通过原位分析检查生物系统内小分子和蛋白质的空间分布。这项研究使用拉曼显微镜光谱法来确定诊断人类骨移植物中表皮葡萄球菌的任何深入的利弊。
方法：使用拉曼显微镜光谱法分析了40个未感染的人骨样品和10个感染表皮葡萄球菌的人骨样品。使用SenterraII显微镜（Bruker，埃特林根,德国)。获取的光谱信息用于光谱和无监督分类，如主成分分析。
结果：拉曼测量产生不同的诊断光谱，用于通过光谱和主成分分析区分未感染的人骨样品和表皮葡萄球菌感染的人骨样品。通过与表皮葡萄球菌共培养的人骨样品检测到骨质量和蛋白质构象的大量损失。使用磷酸盐/酰胺I比率（p=0.030）和碳酸盐/磷酸盐比率（p=0.001）的矿物质与基质的比率表明，细菌感染后骨骼中相对矿物质含量的损失高于未感染的人骨骼。此外，可以检测到胶原网络改变的增加（p=0.048）以及感染的人骨骼中结构组织和相对胶原的减少。随后的主成分分析确定了不同光谱区域的表皮葡萄球菌，分别,主要源自蛋白质的CH2变形（在1450cm-1处）和C-H组的弯曲和拉伸模式（〜2800-3000cm-1）。
结论：拉曼显微光谱法被认为是检测人类骨移植物中表皮葡萄球菌的一种有前途的诊断工具。有必要在人体组织中进行进一步的研究。
方法：使用拉曼显微镜光谱法分析了40个未感染的人骨样品和10个感染表皮葡萄球菌的人骨样品。使用SenterraII显微镜（Bruker，埃特林根,德国)。获取的光谱信息用于光谱和无监督分类，如主成分分析。
结果：拉曼测量产生不同的诊断光谱，用于通过光谱和主成分分析区分未感染的人骨样品和表皮葡萄球菌感染的人骨样品。通过与表皮葡萄球菌共培养的人骨样品检测到骨质量和蛋白质构象的大量损失。使用磷酸盐/酰胺I比率（p=0.030）和碳酸盐/磷酸盐比率（p=0.001）的矿物质与基质的比率表明，细菌感染后骨骼中相对矿物质含量的损失高于未感染的人骨骼。此外，可以检测到胶原网络改变的增加（p=0.048）以及感染的人骨骼中结构组织和相对胶原的减少。随后的主成分分析确定了不同光谱区域的表皮葡萄球菌，分别,主要源自蛋白质的CH2变形（在1450cm-1处）和C-H组的弯曲和拉伸模式（〜2800-3000cm-1）。
结论：拉曼显微光谱法被认为是检测人类骨移植物中表皮葡萄球菌的一种有前途的诊断工具。有必要在人体组织中进行进一步的研究。
