Antibiotic resistance associated with the mcr-1 gene of Gram-negative bacteria, which confers resistance to drugs of last resort and has the potential to spread via plasmids, is one of the most pressing issues facing global health today. Point-of-care testing for the mcr-1 gene is needed to aid in the identification of colistin resistance in the field and to control its horizontal transmission. Here, we report the successful development of an enzyme-free homogenous electrochemical strategy for sensitive detection of the antibiotic resistance gene mcr-1 using the hybridization chain reaction and mcr-1-specific toehold probe. The long double-stranded DNA polymer produced using this strategy could be detected by assessing the diffusion of methylene blue towards the surface of a screen-printed gold electrode. Under optimized conditions, a linear relationship was observed between the variation of peak current and the natural logarithm of the mcr-1 gene concentration in the range of 1 nM to 1 μM with a detection limit of 0.78 nM (S/N = 3). This enzyme-free, isothermal platform is a rapid, portable, disposable, and sensitive method for detection of plasmid-mediated colistin resistance.

与革兰氏阴性细菌的mcr-1基因有关的抗生素耐药性是当今全球卫生领域面临的最紧迫的问题之一，它赋予了对最后药物的耐药性，并有可能通过质粒传播。需要对mcr-1基因进行即时检测，以帮助鉴定现场的粘菌素抗性并控制其水平传播。在这里，我们报告成功开发了一种利用杂交链反应和mcr-1灵敏检测抗生素抗性基因mcr-1的无酶同质电化学策略特定的脚趾探针。通过评估亚甲基蓝向丝网印刷金电极表面的扩散，可以检测出使用该策略生产的长双链DNA聚合物。在优化条件下，观察到峰值电流变化与mcr-1基因浓度的自然对数之间的线性关系，其范围为1 nM至1μM，检出限为0.78 nM（S / N  = 3）。该无酶等温平台是检测质粒介导的粘菌素抗性的快速，便携式，一次性且灵敏的方法。