https://orcid.org/0000-0003-1449-5780
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ABSTRACT
The novel GenePOC/Revogene Carba C assay (GenePOC, Québec, Canada; now Meridian Bioscience, Cincinnati, OH, USA) is a CE-IVD marked, FDA-approved qualitative in vitro diagnostic test for the detection of genes associated with carbapenem-non-susceptibility. Colonies of Enterobacterales can be directly tested without prior DNA isolation. The test consists of a fluorescent-based real-time PCR assay that runs on the centripetal microfluidic revogene platform, providing results within 70 minutes. The assay was evaluated in two studies comprising a total of 294 molecularly characterized clinical Enterobacterales isolates. The overall sensitivity for the detection of carbapenemase gene sequences with the GenePOC assay was 100% (95% CI, 98.4% to 100). Besides the common KPC, VIM, NDM and OXA-48-like carbapenemase genes, also the very variable IMP variants were all detected. The specificity of the assay was 100% (95% CI, 98.8% to 100%). In this article the performance of the GenePOC/Revogene Carba C assay is evaluated and other currently available methods for the detection of carbapenemases are reviewed.
Article highlights
CPE detection is the cornerstone of clinical microbiology diagnostics, including patient management, infection control, epidemiology and surveillance of antimicrobial resistance.
Carbapenemases comprise a large, ever-changing group of β-lactamases present in animals, humans and in the environment. Their diversity is a challenge for the detection and their worldwide dissemination poses a threat to last-resort therapies.
To date, a myriad of carbapenemase detection methods are being developed, with each of them having their own advantages and pitfalls and showing a different performance.
Culture-based methods, such as inhibitor-based disc tests, are an affordable and methodologically simple strategy for CPE detection. Nevertheless, they have long TAT, high false negative/positive rates and are not able to properly discriminate among the different carbapenemases.
Similar to culture-based methods, colorimetric tests are cheap and straightforward, with their TAT being much shorter. However, their interpretation can be challenging with weak or low-level carbapenemase producers.
In contrast to molecular methods, immunochromatographic LFA represent a faster, cheaper and simpler alternative, especially for outbreak investigation, and have a performance which is close to that of PCR. However, given the nature of the provided gene panel, none of them should be used as a stand-alone screening tool but rather as a confirmatory test.
NGS constitutes a promising research tool for the discovery of novel antibiotic resistance determinants or for phylogenetical analysis of new clones. Nonetheless, it depends on curated databases, requires complex bioinformatic pipelines, and the price tag is still high. As a result, NGS is not yet implemented in the routine laboratory for CPE detection.
Rapid, simple, accurate and inexpensive carbapenemase detection methods that can be performed directly from clinical samples in a point-of-care or in a near-patient setting should be developed in order to timely and cost-effectively manage patient diagnosis and treatment, implement appropriate infection control policies and prevent the spread of antimicrobial resistance.
Declaration of interest
A Hamprecht has received research support from GenePOC. The authors have no other relevant affiliations or financial involvement with any organization or entity with a financial interest in or financial conflict with the subject matter or materials discussed in the manuscript apart from those disclosed.
Reviewer disclosures
Peer reviewers on this manuscript have no relevant financial or other relationships to disclose.