Evaluation of a Novel In Vitro Diagnostic Immunoassay for the Rapid Qualitative Detection of KPC, NDM, OXA-48-like, IMP and VIM Carbapenemases

Background/Objectives: The global spread of carbapenemase-producing Gram-negative bacteria (CP-GNB) represents a major clinical challenge, causing severe hospital-acquired infections with limited treatment options. Accurate and rapid detection is essential for guiding antimicrobial therapy and implementing infection control measures. Lateral flow immunoassays (LFIAs) targeting the five main carbapenemase families are increasingly used in routine diagnostics, and many new commercial assays have recently become available, often without thorough assessment. The continuous evolution of these enzymes under antibiotic pressure requires regular reassessment of assay performance. Methods: In this study, we evaluated the Beright Carba-5 assay (Alltest Biotech, Hangzhou, China) targeting the five main carbapenemases (KPC, NDM, OXA-48-like, IMP, and VIM), on a panel of 77 whole-genome sequenced Gram-negative bacterial (GNB) isolates exhibiting reduced susceptibility to carbapenems. Seventy-three were carbapenemase-producing (CP) GNBs, including six VIM-, 18 OXA-48-, 14 KPC-, 9 NDM-, 8 IMP-, 10 multiple carbapenemase-, and eight non-targeted carbapenemase-producers. Results: The assay was rapid and easy to use, showing 100% (CI: 73.54% to 100%) specificity, with no false positive results. However, overall sensitivity of CP-GNB detection was lower than expected at 63.08% (CI: 50.20% to 74.72%), with numerous false negatives, particularly among IMP and NDM producers, and to a lesser extent, KPC producers. Detection was more reliable for VIM and OXA-48-like variants. Practical limitations, including insufficient buffer supply, reduced the number of tested isolates from the planned 100 to 77. Conclusions: Overall, the Beright assay demonstrated insufficient sensitivity for routine diagnostic use.