Methicillin-resistant Staphylococcus aureus (MRSA) is a well-known superbug that has the staphylococcal cassette chromosome mec, a mobile genetic element containing genes that enable resistance to β-lactam antibiotics. Specifically, the mecA gene encodes the penicillin-binding protein PBP2a involved in peptidoglycan biosynthesis, cell-wall formation and resistance to antibiotics. MRSA can be categorized into 13 genotypes that differ in their susceptibility to antibiotics, and PBP2a differs between genotypes. Multiple methods are available for the identification of bacterial genotypes by PCR, but they usually require the lysis of bacterial cells and isolation of nucleic acids. Hu et. al. developed a sensor array for the identification of different MRSA strains on the basis of changes in fluorescence. They synthesized eight fluorescent probes that contained the same core scaffold decorated with diverse pairs of quaternary ammonium salts. The probes emit either blue fluorescence or red fluorescence depending on their conformation. As genotypically distinct MRSA strains have different levels of PBP2a expression, the content and morphology of negatively charged cell-wall components consequently vary as well. Positively charged fluorescent probes thus interact differently with bacterial cell walls from distinct genotypes, which causes conformational changes and different blue/red fluorescence intensity ratios. The ratios are measured in a microplate reader, followed by statistical analysis, which results in a specific fingerprint for each bacterial strain tested. The authors showed that their sensor array can be used for differential sensing of Gram-positive and Gram-negative bacteria and clinically relevant superbugs, in addition to MRSA. The results were in good agreement with those obtained via PCR. Because of its simplicity and practicality, the sensor array could be used for point-of-care diagnostics without the need for isolation of nucleic acids before analysis.

耐甲氧西林金黄色葡萄球菌(MRSA) 是一种众所周知的超级细菌，它具有葡萄球菌盒式染色体 mec，这是一种可移动的遗传元件，含有能够抵抗 β-内酰胺抗生素的基因。具体来说，mecA基因编码参与肽聚糖生物合成、细胞壁形成和抗生素抗性的青霉素结合蛋白 PBP2a。MRSA 可分为 13 种基因型，它们对抗生素的敏感性不同，PBP2a 基因型之间也不同。有多种方法可用于通过 PCR 鉴定细菌基因型，但它们通常需要裂解细菌细胞和分离核酸。胡等。阿尔。开发了一种传感器阵列，用于根据荧光变化识别不同的 MRSA 菌株。他们合成了八种荧光探针，这些探针包含相同的核心支架，并装饰有不同对的季铵盐。探针根据其构象发出蓝色荧光或红色荧光。由于基因型不同的 MRSA 菌株具有不同水平的 PBP2a 表达，因此带负电荷的细胞壁成分的含量和形态也随之变化。因此，带正电荷的荧光探针与来自不同基因型的细菌细胞壁的相互作用不同，这会导致构象变化和不同的蓝/红荧光强度比。这些比率在酶标仪中测量，然后进行统计分析，从而为每个测试的细菌菌株产生特定的指纹。作者表明，除了 MRSA 之外，他们的传感器阵列还可用于革兰氏阳性和革兰氏阴性细菌以及临床相关的超级细菌的差异传感。结果与通过 PCR 获得的结果非常一致。因为它的简单实用，