Klebsiella pneumoniae carbapenemase 2 (KPC-2) is a serine β-lactamase that can hydrolyze almost all β-lactam antibiotics. The drug resistant problem of bacteria expressing carbapenemases is currently a global problem, therefore, rapid and specific detection of pathogenic bacteria is urgent. In order to obtain an aptamer that can specifically recognize bacteria expressing KPC-2, we have established a method called Precision-SELEX. Precision-SELEX combined protein SELEX and bacterium SELEX. In this method, KPC-2 was used as a target protein, and Escherichia coli expressing KPC-2 (KPC-2 E. coli) was used as a target bacterium. After precision-SELEX, the same aptamer named XK-10 that can recognize KPC-2 and KPC-2 E. coli was obtained while the screening process could be shortened to 4 rounds. Dissociation equilibrium constants were calculated as 0.81 nM by SPR. In addition, XK-10 could specifically bind to KPC-2 E. coli, which was confirmed through flow cytometry and molecular Docking Simulations. The high-content imaging method could detect KPC-2 E. coli. In all, the Precision-SELEX provides an accurate and efficient method to screening aptamers for bacteria.

肺炎克雷伯氏菌碳青霉烯酶2（KPC-2）是一种丝氨酸β-内酰胺酶，可水解几乎所有的β-内酰胺抗生素。目前，表达碳青霉烯酶的细菌的耐药性问题是一个全球性的问题，因此，对病原菌进行快速，特异的检测是当务之急。为了获得可以特异性识别表达KPC-2的细菌的适体，我们建立了一种称为Precision-SELEX的方法。Precision-SELEX将蛋白质SELEX和细菌SELEX结合在一起。在该方法中，将KPC-2用作靶蛋白，将表达KPC-2的大肠杆菌（KPC-2 E.coli）用作靶细菌。在Precision-SELEX之后，相同的适配子名为XK-10，可以识别KPC-2和KPC-2大肠杆菌在筛选过程可以缩短到4轮的同时获得 通过SPR将解离平衡常数计算为0.81nM。此外，XK-10可以与KPC-2大肠杆菌特异性结合，这已通过流式细胞仪和分子对接模拟得到了证实。高含量成像方法可以检测KPC-2大肠杆菌。总之，Precision-SELEX提供了一种筛选细菌适体的准确而有效的方法。