Abstract:Objective To evaluate the screening capacity of modified carbapenem inactivation method (mCIM ) and EDTA- carbapenem inactivation method (eCIM)for phenotypic activity of carbapenemase in Enterobacteriaceae bacteria. Methods A total of 102 isolates of carbapenem-resistant Enterobacteriaceae and 53 isolates of carbapenem-sensitive Enterobacteriaceae were selected and the carbapenemase activities were determined by mCIM and eCIM,respectively. Meanwhile,the carbapenem-resistant genes in Enter- obacteriaceae,such as blaKPC-2,blaNDM-1,blaIMP-4,blaVIM-1 and blaOXA-48,were detected by PCR.The consistency of results between phe-notypic screening tests and gene examinations was analyzed statistically. Results Of the 102 carbapenem-resistant Enterobacteriaceae strains,97 strains carrying positive drug-resistance gene were detected by PCR, including blaKPC-2 in 51 strains,blaNDM-1 in 38 strains, blaIMP-4 in 5 strains and both blaKPC-2 and blaNDM-1 in 3 strains. Of the 102 carbapenem-resistant Enterobacteriaceae strains,98 strains were detected to be positive phenotype by mCIM,while the other 4 strains were negative phenotype. Of the 98 mCIM positive strains, 46 strains were eCIM positive and 52 strains were eCIM negative. Of the 53 carbapenem-sensitive strains,the results of PCR and mCIM were both negative. For screening of carbapenemase by mCIM,the sensitivity was 99.0% and the specificity was 96.6%,and the Kappa value for consistency with PCR results was 0.959. For screening metallo-beta-lactamase gene, the sensitivity of eCIM was 93.5%,the specificity was 94.6% and the Kappa value was 0.881. For screening class A carbapenemase gene,the sensitivity of eCIM was 92.6%, the specificity was 95.8%,and the Kappa value was 0.882. Conclusion The combined detections of mCIM and eCIM may effectively screen carbapenemase-producing strains in Enterobacteriaceae,and also distinguish the type of carbapenemase,which should be of great significance for epidemiological investigation and therapy of infectious diseases.