University Hospital for Orthopaedics and Traumatology, Medical University of Innsbruck, Anichstraße 35, 6020, Innsbruck, Austria.
University Clinic for Hearing, Voice and Speech Disorders, Medical University of Innsbruck, Anichstrasse 35, Innsbruck, Austria.
Spectrochim Acta A Mol Biomol Spectrosc. 2022 Nov 5;280:121570. doi: 10.1016/j.saa.2022.121570. Epub 2022 Jun 28.
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.
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 and 3600 cm with a spectral resolution of 4 cm using a Senterra II microscope (Bruker, Ettlingen, Germany). The acquired spectral information was used for spectral and unsupervised classification, such as principal component analysis.
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 CH deformation (wagging) of protein (at 1450 cm) and bending and stretching modes of C-H groups (∼2800-3000 cm).
Raman microscopic spectroscopyis presented as a promising diagnostic tool to detect Staphylococcus epidermidis in human bone grafts. Further studies in human tissues are warranted.
拉曼显微镜光谱学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来研究生物系统中小分子和蛋白质的空间分布。本研究使用拉曼显微镜光谱学来确定在诊断人类骨移植物中的表皮葡萄球菌方面的任何深入优势和劣势。
使用拉曼显微镜光谱学分析了 40 个未感染的人类骨样本和 10 个感染表皮葡萄球菌的人类骨样本。使用 Senterra II 显微镜（德国埃特林根的 Bruker）在 200-3600 cm 之间收集反射率数据，光谱分辨率为 4 cm。获得的光谱信息用于光谱和无监督分类，如主成分分析。
拉曼测量产生了独特的诊断光谱，通过光谱和主成分分析可用于区分未感染的人类骨样本和表皮葡萄球菌感染的人类骨样本。与表皮葡萄球菌共培养的人类骨样本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（p = 0.030）和碳酸盐/磷酸盐比（p = 0.001）的矿物质/基质比表明，细菌感染后骨中相对矿物质含量的损失高于未感染的人类骨。此外，可以检测到胶原网络的改变增加（p = 0.048）以及感染的人类骨中的结构组织和相对胶原减少。随后的主成分分析在不同的光谱区域中分别识别出表皮葡萄球菌，主要来自蛋白质的 CH 变形（摆动）（在 1450 cm 处）和 C-H 基团的弯曲和伸缩模式（约 2800-3000 cm）。
拉曼显微镜光谱学作为一种有前途的诊断工具，可用于检测人类骨移植物中的表皮葡萄球菌。需要在人类组织中进行进一步的研究。
