Microchimica Acta ( IF 5.3 ) Pub Date : 2022-04-01 , DOI: 10.1007/s00604-022-05277-7 Menghuan Yu 1 , Haimei Shi 1, 2 , Shaoning Yu 1, 2 , Li Zhang 3 , Guoqing Qian 2
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Functional bacterial enrichment magnetic beads (Fe3O4@SiO2@Fc-MBL) and Gram staining were combined for the fast diagnosis of infecting bacteria in meningitis. Fe3O4@SiO2@Fc-MBL has excellent microbial binding ability and can be used for bacterial enrichment from cerebrospinal fluid (CSF). The enriched bacteria are recognized by Gram stain at very low concentrations (10 CFU·mL−1). The feasibility of this method was verified by five common bacteria in meningitis infection (Gram-positive: Staphylococcus epidermidis, Staphylococcus haemolyticus, and Staphylococcus capitis; Gram-negative: Klebsiella pneumoniae and Escherichia coli). The extraction efficiency of Fc-MBL-modified Fe3O4 magnetic beads was approximately 90% in artificial CSF for the selected bacteria, with the exception of E. coli (~ 60%). The bacteria were successfully recognized by Gram staining and microscopic observation. Fe3O4@SiO2@Fc-MBL acts by capturing and fixing the bacteria in a magnetic field throughout the experiment. Compared with traditional CSF Gram staining, this new method avoids interference by inflammatory cells and red blood cells during microscopic examination. Furthermore, the sensitivity of this method is much better than the centrifugation smear method. The whole process can be accomplished within 30 min. This novel method may have potential as a clinical tool for analysis of bacteria in the CSF.
Graphical abstract
中文翻译：
Fc-MBL 修饰的 Fe3O4 磁珠在革兰氏染色中的富集和固定，用于快速检测低浓度细菌
功能性细菌富集磁珠（Fe 3 O 4 @SiO 2 @Fc-MBL）与革兰氏染色相结合，用于脑膜炎感染菌的快速诊断。Fe 3 O 4 @SiO 2 @Fc-MBL 具有优异的微生物结合能力，可用于脑脊液（CSF）中的细菌富集。富集的细菌在极低浓度 (10 CFU·mL -1 ) 下被革兰氏染色识别。该方法的可行性已通过脑膜炎感染中的五种常见细菌（革兰氏阳性：表皮葡萄球菌、溶血葡萄球菌和头状葡萄球菌）验证。; 革兰氏阴性：肺炎克雷伯菌和大肠杆菌）。Fc-MBL 修饰的 Fe 3 O 4磁珠在人工脑脊液中对选定细菌的提取效率约为 90%，但大肠杆菌除外(~ 60%)。通过革兰氏染色和显微镜观察成功识别细菌。Fe 3 O 4 @SiO 2@Fc-MBL 在整个实验过程中通过在磁场中捕获和固定细菌来发挥作用。与传统的脑脊液革兰染色相比，这种新方法在显微镜检查过程中避免了炎症细胞和红细胞的干扰。此外，该方法的灵敏度远优于离心涂片法。整个过程可以在30分钟内完成。这种新方法可能具有作为分析脑脊液中细菌的临床工具的潜力。
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