头孢他啶-阿维巴坦的使用越来越多,导致出现了多种抗头孢他啶-阿维巴坦的blaKPC-2变体。特别是,传统的碳青霉烯酶表型分析显示KPC-2变异体的假阴性率高.在这项研究中,三种胶体金免疫测定,包括黄金山河CGI测试,DynamikerCGI测试和NG-TestCARBA5,以及GeneXpertCarba-R,用于检测42株肺炎克雷伯菌中KPC-2碳青霉烯酶及其各种变体的存在。这些菌株涵盖了blaKPC-2(13/42)和其他16种blaKPC-2变体,包括blaKPC-12(1/42),blaKPC-23(1/42),blaKPC-25(1/42),blaKPC-33(6/42),blaKPC-35(1/42),blaKPC-44(1/42),blaKPC-71(1/42),blaKPC-76(8/42),blaKPC-78(1/42),blaKPC-79(1/42),blaKPC-100(1/42),blaKPC-127(1/42),blaKPC-128(1/42),blaKPC-144(1/42),blaKPC-157(2/42),和blaKPC-180(1/42)。对于KPC-2菌株,所有4种检测方法均显示与测序结果100%阴性百分比一致性(NPA)和100%阳性百分比一致性(PPA).对于所有16个KPC-2变体,GeneXpertCarba-R显示100%NPA和100%PPA,三个胶体金免疫测定显示100%NPA,而黄金山河CGI测试的PPA,DynamikerCGI测试,NG-TestCARBA5为87.5%,87.5%,和68.8%,分别。我们还发现变体氨基酸中的突变位点与胶体金免疫测定的假阴性结果之间存在相关性。总之,GeneXpertCarba-R已被证明是检测KPC-2及其变体的可靠方法,胶体金免疫测定测试为其检测提供了一种实用且具有成本效益的方法。对于胶体金免疫测定结果为阴性但与耐药表型不匹配的样品,建议使用另一种类型的试剂盒或GeneXpertCarba-R测定进行重新测试,可以显著提高检测的准确性。
The increasing use of ceftazidime-avibactam has led to the emergence of a wide range of ceftazidime-avibactam-resistant blaKPC-2 variants. Particularly, the conventional carbapenemase phenotypic assay exhibited a high false-negative rate for KPC-2 variants. In this study, three colloidal gold immunoassays, including the Gold Mountainriver CGI test, Dynamiker CGI test and NG-Test CARBA5, and GeneXpert Carba-R, were used to detect the presence of KPC-2 carbapenemase and its various variants in 42 Klebsiella pneumoniae strains. These strains covered blaKPC-2 (13/42) and 16 other blaKPC-2 variants including blaKPC-12 (1/42), blaKPC-23 (1/42), blaKPC-25 (1/42), blaKPC-33 (6/42), blaKPC-35 (1/42), blaKPC-44 (1/42), blaKPC-71 (1/42), blaKPC-76 (8/42), blaKPC-78 (1/42), blaKPC-79 (1/42), blaKPC-100 (1/42), blaKPC-127 (1/42), blaKPC-128 (1/42), blaKPC-144 (1/42), blaKPC-157 (2/42), and blaKPC-180 (1/42). For KPC-2 strains, all four assays showed 100% negative percentage agreement (NPA) and 100% positive percentage agreement (PPA) with sequencing results. For all 16 KPC-2 variants, GeneXpert Carba-R showed 100% NPA and 100% PPA, and the three colloidal gold immunoassays showed 100% NPA, while the PPAs of the Gold Mountainriver CGI test, Dynamiker CGI test, and NG-Test CARBA5 were 87.5%, 87.5%, and 68.8%, respectively. We also found a correlation between the mutation site in the amino acid of the variants and false-negative results by colloidal gold immunoassays. In conclusion, the GeneXpert Carba-R has been proven to be a reliable method in detecting KPC-2 and its variants, and the colloidal gold immunoassay tests offer a practical and cost-effective approach for their detection. For the sample with a negative result by a colloidal gold immunoassay test but not matching the drug-resistant phenotype, it is recommended to retest using another type of kit or the GeneXpert Carba-R assay, which can significantly improve the accuracy of detection.