Methods for bacterial detection are needed to advance the infection research and diagnostics. Based on conformation-sensitive fluorescent tracer molecules, optotracing was recently established for dynamic detection and visualization of structural amyloids and polysaccharides in the biofilm matrix of gram-negative bacteria. Here, we extend the use of optotracing for detection of gram-positive bacteria, focussing on the clinically relevant opportunistic human pathogen Staphylococcus aureus. We identify a donor-acceptor-donor-type optotracer, whose binding-induced fluorescence enables real-time detection, quantification, and visualization of S. aureus in monoculture and when mixed with gram-negative Salmonella Enteritidis. An algorithm-based automated high-throughput screen of 1920 S. aureus transposon mutants recognized the cell envelope as the binding target, which was corroborated by super-resolution microscopy of bacterial cells and spectroscopic analysis of purified cell wall components. The binding event was essentially governed by hydrophobic interactions, which permitted custom-designed tuning of the binding selectivity towards S. aureus versus Enterococcus faecalis by appropriate selection of buffer conditions. Collectively this work demonstrates optotracing as an enabling technology relevant for any field of basic and applied research, where visualization and detection of S. aureus is needed.

需要细菌检测方法来推进感染的研究和诊断。基于构象敏感的荧光示踪剂分子，最近建立了光示踪技术，用于动态检测和可视化革兰氏阴性细菌生物膜基质中的结构淀粉样蛋白和多糖。在这里，我们扩展了光跟踪技术在革兰氏阳性细菌检测中的应用，重点是临床相关的机会性人类病原体金黄色葡萄球菌。我们确定了一个供体-受体-供体型光示踪剂，其结合诱导的荧光使得单培养中以及与革兰氏阴性沙门氏菌混合时的金黄色葡萄球菌的实时检测，定量和可视化成为可能。肠炎。基于算法的1920年金黄色葡萄球菌转座子突变体的自动高通量筛选将细胞包膜识别为结合靶标，这通过细菌细胞的超高分辨率显微镜检查和纯化的细胞壁成分的光谱分析得到了证实。该结合事件基本上是由疏水性相互作用，这允许定制设计的结合选择性的调谐向管辖金黄色葡萄球菌对粪肠球菌通过的缓冲条件适当选择。总的来说，这项工作证明了光跟踪技术是与基础和应用研究的任何领域相关的使能技术，在这些领域中，需要对金黄色葡萄球菌进行可视化和检测。