Direct detection of major carbapenemases from positive blood cultures using the NG-TEST® Blood Culture PREP kit combined with NG-TEST® CARBA 5

Abstract

Background Rapid detection of Gram-negative carbapenemase-producing organisms (CPOs) in bloodstream infections is crucial to guide timely therapy. We assessed the performance of the NG-TEST ® CARBA 5 (NG Biotech) combined with the NG-TEST ® Blood Culture PREP (BCP) Kit for direct detection of the five main carbapenemases from positive blood cultures. Methods A total of 145 clinical Enterobacterales were used to spike blood culture bottles. These included 124 CPOs with targeted carbapenemases (18 NDM-, 10 VIM-, 28 IMP-, 24 KPC-, 31 OXA-48-like, and 13 multiple carbapenemases), 10 CPOs with no targeted carbapenemases, and 11 non-CPOs. Blood cultures were placed in the BACT/ALERT ® VIRTUO® system (bioMérieux) until bacterial growth was detected by the system. Bacteria were produced using the NG-TEST ® BCP Kit, followed by the NG-TEST ® CARBA 5. The results were compared to those from colonies. Results The NG-TEST ® BCP Kit reliably extracted bacteria irrespective of the bacterial species. The NG-TEST ® CARBA 5 identified 134 of the 138 carbapenemases from bacterial pellets from blood cultures and 136 of the 138 from bacterial colonies, resulting in 97.10% and 98.55% sensitivity, respectively. As expected, KPC-31 and KPC-33 were missed in both cases, but two VIM-producing C. freundii were only detected from colonies. Non-targeted CPOs and non-CPOs gave negative results, confirming 100% specificity. Conclusion Our results show that combining the NG-TEST ® BCP Kit with the NG-TEST ® CARBA 5 provides a rapid (<25 min), user-friendly, robust, and accurate method for species-independent detection of the five main carbapenemases directly from positive blood cultures, enabling earlier targeted antimicrobial therapy in bloodstream infections.

The authors' abstract, as published at the source. Frontiers in Microbiology, 2026 · DOI ↗