Rapid and easy detection of carbapenemases in Enterobacterales in the routine laboratory using the new GenePOC™ Carba/Revogene™ Carba C assay.

Background: The novel real-time PCR-based Carba assay on the microfluidic platform revogene (GenePOC™, Québec City, QC, Canada, now Meridian Bioscience, Cincinnati, US) has been recently designed for the detection of bla KPC , bla NDM , bla VIM , bla OXA-48-like and bla IMP The goal of this study was to evaluate the performance of this assay, assess its suitability in the routine microbiology laboratory and compare it to the Xpert Carba-R for the detection of carbapenemase producing Enterobacterales (CPE). Methods: The Xpert Carba-R (Cepheid) and the GenePOC™ Carba assay were challenged with a collection of 176 clinical Enterobacterales isolates. The collection was composed of 133 CPE producing a total of 139 carbapenemases, including VIM (n=48), OXA-48-like (n=40), NDM (n=29), KPC (n=13) and IMP (n=9). Six isolates produced two different carbapenemases, and 43 carbapenemase-negative isolates were included as negative controls. Results: The overall sensitivity for carbapenemase detection was 96.4% (CI 91.9%-98.5%) for Xpert Carba-R and 100% (CI 97.3%-100%) for GenePOC. The four most common carbapenemases (NDM, KPC, OXA-48-like, VIM) were detected with a sensitivity of 100% (CI 97.1%-100%) by the two tests, with all double carbapenemase producers being correctly detected by both assays. The sensitivity of Xpert Carba-R for IMP was 44.4% (CI 18.9%-73.3%), while that of GenePOC was 100% (CI 70.1%-100%). The specificity of both assays was 100% (CI 91.8%-100%). Conclusions: The GenePOC Carba assay showed excellent sensitivity and specificity for the five most common carbapenemases including IMP variants. Its simplicity and short turnaround time make it suitable for use in the routine microbiology laboratory for CPE detection.