Evaluation of the BD Phoenix CPO detect panel for prediction of Ambler class carbapenemases

Daniel Jonas,Hajo Grundmann,Sandra Reuter,Marion Buck,Sarah Klassen,Tommaso Giani,Gian Maria Rossolini,Sabine Weber

doi:10.1038/s41598-021-92336-3

Abstract

Rapid detection of carbapenemases as a cause of resistance is beneficial for infection control and antimicrobial therapy. The BD Phoenix NMIC-502 panel and CPO detect test identifies presence of carbapenemases in Enterobacterales such as Klebsiella pneumoniae and assigns them to Ambler classes. To evaluate the performance of the CPO detect panel, we employed a European collection of 1222 K. pneumoniae including carbapenem non-susceptible and susceptible clinical isolates from 26 countries, for which draft genomes were available after Illumina sequencing and the presence of carbapenemase genes had been identified by ARIBA gene calling. The CPO panel detected 488 out of 494 carbapenemase-encoding isolates as positive and six as negative. One-hundred and two isolates were tested positive for carbapenemase in the absence of any carbapenemase gene. The CPO panel identified 229 out of 230 KPC-positive isolates as carbapenemase producing and classified 62 of these as class A enzyme. Similarly, the CPO panel correctly specified 167 of 182 as class D. Regarding metallo-beta-lactamases, the CPO panel assigned 78 of 90 MBL positive isolates to class B enzymes. The sensitivity of the CPO panel in detecting carbapenemase activity was 99.5%, 97.7% and 98.3% for class A, B and D enzymes, respectively. The sensitivity in assignation to Ambler class A, B and D was 27%, 86% and 91%, respectively. An overall sensitivity of 98.8% and specificity of 86% in unclassified detection of carbapenemases was observed, with frequent false positive detection of carbapenemase producing organisms, thus rendering further confirmatory tests necessary.

Highlights

In accordance with antimicrobial susceptibility testing (AST), the carbapenemase-producing organisms (CPO) panel can distinguish carbapenem resistances due to carbapenemase production from those mediated by other mechanisms (e. g. altered permeability) in Enterobacterales such as Klebsiella pneumoniae
Resolution of 15 initially discrepant results between positive sequence data and negative phenotypic CPO panel results using gene-specific PCR resulted in 9 PCR negative results and 6 strains that remained positive for carbapenemase sequences based on both the sequence data and the PCR results
Previous studies on the performance of the CPO detect panel were hampered by employing strains of mainly regional origin (e.g., Louisiana, Singapore and South of Germany)

Summary

Evaluation of the BD Phoenix

Daniel Jonas1*, Sandra Reuter[1], Sarah Klassen[1], Sabine Weber[1], Marion Buck[1], Tommaso Giani[2,3], Gian Maria Rossolini2,3 & Hajo Grundmann[1]. To evaluate the performance of the CPO detect panel, we employed a European collection of 1222 K. pneumoniae including carbapenem non-susceptible and susceptible clinical isolates from countries, for which draft genomes were available after Illumina sequencing and the presence of carbapenemase genes had been identified by ARIBA gene calling. The study presented here is a large evaluation of the performance of the CPO detection test included in the BD PhoenixTM NMIC-502 panel for (i) detection and (ii) classification of carbapenemases It is based on a representative European collection of over 1000 Klebsiella pneumoniae isolates from 26 countries which originated from surveillance of carbapenem resistance throughout Europe in 2014, and all of which had previously been subjected to WGS analysis[31].

Results

Discussion

Methods