Methodological Evaluation of Carbapenemase Detection by Different Methods

The global proliferation of carbapenemase-producing bacteria (CPB) has garnered significant attention worldwide. Early diagnosis of CPB and accurate identification of carbapenemases are crucial for preventing the spread of CPB and ensuring targeted antibiotic therapy. Therefore, efficient and accurate identification of carbapenemases is paramount in clinically treating diseases associated with CPB. In this study, 58 CPB strains were collected and detected using the DNA endonuclease-targeted CRISPR trans reporter (DETECTR) method, a rapid detection platform based on CRISPR-Cas12a gene editing and isothermal amplification. Additionally, four conventional methods (the APB/EDTA method, PCR, NG-test Carba 5, and GeneXpert Carba-R) were employed and compared against whole genome sequencing (WGS) results, considered the gold standard, to evaluate their efficacy in detecting carbapenemases. Detection by the APB/EDTA method revealed that 29 strains were positive for Class A serine endopeptidases, while 29 strains were positive for Class B metalloenzymes. The classification of these zymotypes was consistent with the sequencing result. All target carbapenemases for KPC were identified with 100% sensitivity using NG-test Carba 5, PCR, DETECTR, and GeneXpert Carba-R. In the case of NDM, both Xpert Carba-R and DETECTR showed a sensitivity of 100%. In contrast, NG-test Carba 5 and PCR had a slightly lower sensitivity of 96.7%, each missing one target carbapenemase. n this study, the APB/EDTA method is capable of identifying the zymotype classification but not the specific resistant genes, while Xpert Carba-R and DETECTR are able to detect all target carbapenemases.