关键词: 碳青霉烯酶, NG-Test CARBA 5, Carba NP试验

Abstract: Objective To explore the application value of NG-Test CARBA 5 in the detection of carbapenemase content in blood cultured enterobacteriaceae bacteria. 
Methods A total of 62 strains of enterobacteriaceae bacteria with known gene types were collected from clinical specimens of our hospital, including 38 strains of carbapenem resistant enterobacteriaceae bacteria and 24 strains of carbapenem sensitive enterobacteriaceae bacteria. NG-Test CARBA 5 kit, Carba NP and mCIM tests were used to detect the major carbapenemases of the strains to be tested, and PCR was used to sequence the carbapenemase gene phenotypes for confirmation and Kappa consistency test. Then 20 strains were randomly selected from 38 carbapenem resistant strains for simulated blood culture, and tested with NG-Test CARBA 5 kit, Carba NP method and mCIM method and Kappa consistency test. 
Results The drug resistance of 38 carbapenem resistant Enterobacteriaceae strains were meropenem and/or imipenem. PCR amplification and sequencing results showed that 33 strains carried drug resistance genes, and 5 strains did not carry common drug resistance genes. The sensitivity and specificity of NG-Test CARBA 5 in detecting KPC, NDM, IMP, KPC+NDM and NDM+IMP within 15 min were 100%.The sensitivity of Carba NP method and mCIM method was 93.94% and 96.97%, respectively, and the specificity was 80.00% and 100.00%, respectively. The Kappa values were 0.857 and 0.902 (P＜0.05), which were consistent with the results of gene sequencing. Twenty carbapenem resistant Enterobacteriaceae bacteria were cultured in simulated blood. There were 6, 5, 4 and 5 strains of Escherichia coli, Enterobacter cloacae, Klebsiella pneumoniae and Klebsiella acidogenes, respectively. The sensitivity and specificity of NG-Test CARBA 5 were 100.0%, and the Kappa value was 1.000, which were consistent with the results of gene sequencing. The sensitivity of Carba NP method and mCIM method were 87.50% and 93.75% respectively, and the specificity was 100%. The Kappa values were 0.812 and 0.898 (P＜0.05), which were consistent with the results of gene sequencing. 
Conclusion The detection process of NG-Test CARBA5 is simple, efficient and accurate, which greatly simplifies the complex process of clinical detection of carbapenemase, and is helpful to enhance hospital infection control and timely guide clinical treatment. 

Key words: carbapenemase, NG-Test CARBA 5, Carba NP test