Evaluation of NG-Test Carba 5 for Rapid Phenotypic Detection and Differentiation of Five Common Carbapenemase Families: Results of a Multicenter Clinical Evaluation

Abstract

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.

Carbapenemase detection by NG-Test CARBA 5—a rapid immunochromatographic assay in carbapenem-resistant Enterobacterales diagnosis

“…The global spread of carbapenem-resistant Enterobacterales (CRE) represents a serious public health concern as these pathogens are associated with limited treatment options, high mortality rate and rapid transmissibility (1,2). Mechanisms underlying carbapenem resistance are related mainly to the production of carbapenemases (carbapenemase-producing Enterobacterales, CP-CRE), but also a consequence of decreased membrane permeability coupled with the overexpression of extended-spectrum β-lactamases (ESBLs) or AmpC β-lactamases (non-carbapenemase-producing carbapenem-resistant Enterobacterales, non-CP-CRE) (3)(4)(5). Detection of the mechanisms of carbapenem resistance is not routinely performed in many Chinese hospitals.…”

“…Detection of the mechanisms of carbapenem resistance is not routinely performed in many Chinese hospitals. However, the distinction between CP-CRE and non-CP-CRE is valuable for infection control as CP-CRE can spread rapidly through horizontal gene transfer among Gram-negative organisms and therefore may require implementation of intensive infection control interventions (3,5). Moreover, novel antimicrobial agents possess unique profiles in their activities against different carbapenemases.…”

Expressed and Silent Carbapenemase Genes Detected by Multiplex PCR in both Carbapenem-Resistant and Phenotypically-Susceptible Gram Negative Bacilli

“…Several diagnostic modalities have been recognized based on the detection of carbapenem-hydrolyzing activity. Additionally, several phenotypic confirmatory tests have also been implemented, such as NG-test CARBA 5, Xpert Carba-R, mCIM, and eCIM [5].…”

Multiplex Lateral Flow Immunochromatographic Assay Is an Effective Method to Detect Carbapenemases Without Risk of OXA-48-like Cross Reactivity

“…Previous studies evaluating the CARBA 5 assay found a sensitivity ranging from 88-100% and a speci city varying between 95-100% [7][8][9][10][11][12][13][14][15]29]. Three of these studies demonstrated 100% agreement [7,12,15].…”

“…In the CARBA 5 assay, cross reactivity may occur if an isolate harboring an OXA-type variant reacts incorrectly with the OXA-48-like target, leading to a false positive result. Several studies have evaluated the CARBA 5 assay and found high sensitivity and speci city rates [7][8][9][10][11][12][13][14][15], yet only two of these studies evaluated the cross reactivity of other OXA-type carbapenemases with the OXA-48-like speci c antibodies [9,14]. Here, we aimed to evaluate the CARBA 5 assay for detection of carbapenemases and to assess its speci city towards other OXA-type carbapenemases.…”