Di-san junyi daxue xuebao (Mar 2020)

Evaluation on clinical application of mCIM and eCIM in detection of cabapenemase from Enterobacteriaceae Bateremia

  • WANG Yonghong,
  • WANG Yonghong,
  • LIU Hang,
  • ZOU Jiaqi,
  • MA Hualan2,
  • XIA Yun

DOI
https://doi.org/10.16016/j.1000-5404.201909092
Journal volume & issue
Vol. 42, no. 5
pp. 466 – 472

Abstract

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Objective To evaluate the performance of modified carbapenem inactivation method (mCIM) and EDTA carbapenem inactivation method (eCIM) in detection of carbapenemase in Enterobacteriaceae Bateremia. Methods Polymerase chain reaction (PCR) was used to detect carbapenemase gene in 136 strains of carbapenem-resistant and -sensitive Enterobacteriaceae clinically isolated from 16 county-level hospital during January 2017 and September 2018. Meanwhile, the phenotype of obtained carbapenemase gene was screened by mCIM and eCIM. The results of gene detection and phenotypic screening test were analyzed and evaluated. Results Seventy-nine strains out of 85 carbapenem-resistant Enterobacteriaceae strains (CRE) were positive to carbapenemase gene by PCR, and 8 strains expressed class A and B carbapenemase gene, accounting for 10.13% (8/79). Seventy-eight strains of 85 CRE strains were positive detected by mCIM, and 44 strains were identified to be positive by eCIM among them. The carbapenem-resistant genes were not detected in the 51 carbapenem-sensitive strains by mCIM results. Screening the carbapenemase by mCIM had the sensitivity of 98.7% (95%CI: 92.2~99.9), the specificity of 100.0% (95%CI: 92.1~100.0), and the Kappa value of 0.985. When eCIM screened metallo-β-lactamase, the sensitivity was 85.7% (95%CI: 72.1~93.6), the specificity was 94.4%(95%CI: 80.0~99.0), and the Kappa value was 0.787. Screening serine carbapenemase, the sensitivity of eCIM was 89.5%(95%CI: 74.3~96.6), the specificity was 100.0%(95%CI: 90.6~100.0), and the Kappa value was 0.904. Conclusion Combination of mCIM and eCIM can screen carbapenemase-producing Enterobacteriaceae effectively. However, the sensitivity of the combined detection to screen metallo-β-lactamase will be reduced with the emergence of a large number of co-expressed class A and B carbapenemase-producing Enterobacteriaceae.

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