Evaluation of BD Phoenix CPO Detect and NG-Test CARBA 5 for the detection and classification of carbapenemase-producing Enterobacterales using whole-genome sequencing as the reference standard

Rapid detection and accurate classification of carbapenemase-producing Enterobacterales (CPE) are essential for antimicrobial stewardship and infection prevention. We evaluated the performance of the BD Phoenix CPO Detect (BD-CPO) assay and the NG-Test CARBA 5 (NG-C5) using whole-genome sequencing (WGS) as the reference standard in a tertiary pediatric center. A total of 161 non-duplicate WGS-confirmed CPE isolates recovered from clinical and screening specimens were included. NG-C5 demonstrated a sensitivity of 99.4%, correctly identifying and classifying carbapenemase genes in 160 of 161 isolates, including those harboring dual carbapenemase genes. BD-CPO showed a sensitivity of 96.3% (155/161) for CPE detection; however, accurate Ambler class assignment was achieved in only 70.2% (113/161) of isolates. Misclassification occurred in 9.3% (15/161) of isolates, and six false-negative results (3.7%) were observed with the BD-CPO test, particularly among isolates harboring bla OXA genes. Both assays provide rapid detection of carbapenemase production compared to conventional phenotypic methods. However, NG-C5 demonstrated superior performance in carbapenemase gene identification and classification. Implementation of rapid carbapenemase detection assays can support timely therapeutic optimization and infection control interventions, although the results should be interpreted within a comprehensive diagnostic framework that includes molecular confirmation and full antimicrobial susceptibility testing. IMPORTANCE Accurate detection of carbapenemase-producing Enterobacterales (CPE) is critical for guiding targeted antimicrobial therapy and implementing effective infection control strategies. Clinical microbiology laboratories rely on a variety of phenotypic and rapid diagnostic methods; however, their ability to correctly detect and classify carbapenemases remains variable. In this study, we compared the performance of the BD Phoenix CPO Detect and NG-Test CARBA 5 using whole-genome sequencing as the reference standard. Our results demonstrate important differences in diagnostic accuracy, particularly for OXA-type carbapenemases, providing practical evidence to guide laboratories in selecting reliable tools for rapid CPE detection and classification.