Abstract:
                                      OBJECTIVE To evaluate the performance and clinical value of Carba plus disc in detection of carbapenemases. 
METHODS Totally 77 strains of carbapenem-resistant 
Enterobacteriaceae(CRE) that were isolated from Daping Hospital, Army Medical University from Jan 2017 to Dec 2017 were assigned as the experimental group, meanwhile, 84 strains of carbapenem-sensitive 
Enterobacteriaceae(CSE) were set as the control group.The drug resistance genes of all the strains were detected, the Carba plus disc detection was performed, the result of detection of the drug resistance genes was set as the gold standards for identification of carbapenemases, and the performance indexes of Carba plus disc method in detection of carbapenemases were statistically analyzed. 
RESULTS The result of drug resistance gene sequencing analysis of the 77 strains of CRE showed that there were 51 
KPC-positive strains, 22 
MBL-positive strains and 4 
OXA-48-positive strains.The result of Carba plus disc detection indicated that there were 42 
KPC-positive strains, 26 
MBL-positive strains and 5 
OXA-48-positive strains, while, there were 4 strains that were not detected with any enzyme-producing genotype.The sensitivity of the Carba plus disc method was 82.3% in prediction of KPC, the specificity 100.0%, the positive predictive value 100.0%, the negative predictive value 92.4%, the accuracy 94.4%; the sensitivity was 100.0% in prediction of MBL, the specificity 97.1%,the positive predictive value 84.6%,the negative predictive value 100.0%, the accuracy 97.5%; the sensitivity was 100.0% in prediction of 
OXA-48,the specificity 99.4%, the positive predictive value 80.0%,the negative predictive value 100.0%,the accuracy 99.4%. 
CONCLUSION Carba plus disc method may contribute to the rapid, accurate and convenient identification of the carbapenemases of the CRE strains, it has a promising future in grass-roots microbiology laboratories and can be used as a major mean for phenotypic confirmation tests and monitoring of drug resistance.