Raman Spectroscopy—A Novel Method for Identification and Characterization of Microbes on a Single-Cell Level in Clinical Settings

Abstract

Rapid and accurate identification of pathogens causing infections is one of the biggest challenges in medicine. Timely identification of causative agents and their antimicrobial resistance profile can significantly improve the management of infection, lower costs for healthcare, mitigate ever-growing antimicrobial resistance and in many cases, save lives. Raman spectroscopy was shown to be a useful—quick, non-invasive, and non-destructive —tool for identifying microbes from solid and liquid media. Modifications of Raman spectroscopy and/or pretreatment of samples allow single-cell analyses and identification of microbes from various samples. It was shown that those non-culture-based approaches could also detect antimicrobial resistance. Moreover, recent studies suggest that a combination of Raman spectroscopy with optical tweezers has the potential to identify microbes directly from human body fluids. This review aims to summarize recent advances in non-culture-based approaches of identification of microbes and their virulence factors, including antimicrobial resistance, using methods based on Raman spectroscopy in the context of possible use in the future point-of-care diagnostic process.

Contemporary strategies and approaches for characterizing composition and enhancing biofilm penetration targeting bacterial extracellular polymeric substances

“…When a transparent sample is illuminated with monochromatic light, the majority of the light passes through, while a small amount is scattered in all directions. Light scattering can be classified into Rayleigh scattering and Raman scattering [ 92 ]. Rayleigh scattering occurs when an elastic collision happens between photons and sample molecules, where no energy exchange transpires between the photon and the molecules.…”

A case of <italic>Elizabethkingia meningoseptica</italic> septicemia

“…实验室一般通过纸片扩散法、浓度梯度法（E-test试验）和稀释法来确定菌株对抗菌药物的敏感性。针对伊丽莎白金菌，国际上一般推荐微量肉汤稀释法 ［ 14 ］ ，但目前尚无伊丽莎白金菌最低抑菌浓度的标准，临床主要参考的是美国临床实验室标准化研究所和/或欧洲抗微生物药物敏感性试验委员会制订的标准 ［ 1 ］ 。拉曼光谱分析法可以快速、有效地鉴定细菌及其对抗菌药物的敏感性，目前已成为鉴定细菌耐药的新方法。随着材料科学、纳米技术和光学技术的发展，已有文献报道多种类型的拉曼光谱研究用于检测多种细菌的耐药性表型，如SERS、离心分离法+拉曼光谱、磁珠技术+SERS、介电电泳+拉曼光谱、微流控SERS芯片、拉曼镊子（光镊Optical Tweezers+拉曼光谱）、单细胞拉曼光谱等 ［ 15 ］ 。据文献研究报道，单细胞拉曼-重水标记可直接应用于低至10 6 CFU/mL的伊丽莎白菌血培养标本，从而用于伊丽莎白菌血流感染的临床诊断。用单细胞拉曼-重水标记法和传统微量肉汤稀释法检测伊丽莎白金菌对7种抗菌药物（氨曲南、亚胺培南、替卡西林/克拉维酸、阿米卡星、妥布霉素、米诺环素、左氧氟沙星）的敏感性，两者结果一致，但单细胞拉曼-重水标记法获得药敏试验结果仅需4 h左右，比微量肉汤稀释法快4~5倍 ［ 16 ］ 。研究还表明，单细胞拉曼-重水标记法也可以推广到脑脊液和其他体液中伊丽莎白菌的药敏测试 ［ 16 ］ 。…”

Illuminating the Tiny World: A Navigation Guide for Proper Raman Studies on Microorganisms

“…On the one hand, Raman spectroscopy, as a vibrational spectroscopic technique, enables the identification of bacteria using their optical fingerprint [ 3 , 4 , 5 , 6 , 7 , 8 , 9 ]. On the other hand, Raman spectroscopy can be used to monitor chemical changes in bacterial cells [ 10 , 11 , 12 , 13 ].…”