Evaluation of ng-test carba 5 for rapid phenotypic detection and differentiation of five common carbapenemase families: results of a multicenter clinical evaluation

Stephen Jenkins, Nathan A. Ledeboer, Lars F. Westblade, Carey Ann D. Burnham, Matthew L. Faron, Yehudit Bergman, Rebecca Yee, Brian Mesich, Derek Gerstbrein, Meghan A. Wallace, Amy Robertson, Kathy A. Fauntleroy, Anna S. Klavins, Rianna Malherbe, Andre Hsiung, Patricia J. Simner*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

28 Scopus citations


NG-Test Carba 5 is a rapid in vitro multiplex immunoassay for the phenotypic detection and differentiation of five common carbapenemase families (KPC, OXA-48-like, VIM, IMP, and NDM) directly from bacterial colonies. The assay is simple to perform and has recently received U.S. Food and Drug Administration clearance. A method comparison study was performed at geographically diverse medical centers (n = 3) in the United States, where 309 Enterobacterales and Pseudomonas aeruginosa isolates were evaluated by NG-Test Carba 5 (NG Biotech, Guipry, France), the Xpert Carba-R assay (Cepheid, Inc., Sunnyvale, CA), the modified carbapenem inactivation method (mCIM), the EDTA-modified carbapenem inactivation method, and disk diffusion with carbapenems. Colonies from tryptic soy agar with 5% sheep blood (blood agar) and MacConkey agar were tested, and the results were compared to those obtained by a composite reference method. Additionally, a fourth medical center performed a medium comparison study by evaluating the performance characteristics of NG-Test Carba 5 from blood, MacConkey, and Mueller-Hinton agars with 110 isolates of Enterobacterales and P. aeruginosa. These results were compared to the expected genotypic and mCIM results. For the multicenter method comparison study, the overall positive percent agreement (PPA) and the overall negative percent agreement (NPA) of NG-Test Carba 5 with the composite reference method were 100% for both blood and MacConkey agars. The medium comparison study at the fourth site showed that the PPA ranged from 98.9% to 100% and that the NPA ranged from 95.2% to 100% for blood, MacConkey, and Mueller-Hinton agars. NG-Test Carba 5 accurately detected and differentiated five common carbapenemase families from Enterobacterales and P. aeruginosa colonies on commonly used agar media. The results of this test will support a streamlined laboratory work flow and will expedite therapeutic and infection control decisions.

Original languageAmerican English
Article numbere00344-20
JournalJournal of Clinical Microbiology
Issue number7
StatePublished - Jul 2020
Externally publishedYes

Bibliographical note

Publisher Copyright:
Copyright © 2020 American Society for Microbiology. All Rights Reserved.


  • Carbapenemase
  • ECIM
  • Enterobacterales
  • MCIM
  • NG-Test Carba 5
  • Pseudomonas aeruginosa
  • Xpert Carba-R


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