Diagnostic accuracy of the RESIST-5 O.K.N.V.I. immunochromatographic assay for detection of carbapenemase-producing Gram-negative bacteria: comparison with real-time PCR.

Gram-negative bacteria resistant to carbapenems have now become a major global health threat due to limited therapeutic options and high mortality. Rapid and accurate detection of carbapenemase genes is crucial for targeted antimicrobial treatment and infection control. This study evaluated the diagnostic performance of the RESIST-5 O.K.N.V.I. immunochromatographic test (ICT) compared with real-time polymerase chain reaction (RT-PCR) to detect major carbapenemase genes. A prospective diagnostic accuracy study included 252 clinical isolates of Gram-negative bacteria resistant to carbapenem. The ICT assay was evaluated for detection of five major carbapenemase genes (blaNDM, blaKPC, blaVIM, blaIMP, blaOXA-48), using RT-PCR as the reference standard. Sensitivity, Specificity, Positive Predictive Value (PPV), and Negative Predictive Value (NPV) were calculated. The gene-level ICT assay showed a final sensitivity of 99.66% (95% CI: 98.11-99.94) and a specificity of 99.90% (95% CI: 99.42-99.98), with a PPV of 99.66% (95% CI: 98.11-99.94) and an NPV of 99.90% (95% CI: 99.42-99.98). The RESIST-5 O.K.N.V.I. ICT assay provides a rapid and practical approach for screening of major carbapenemase genes. However, blaKPC-specific sensitivity could not be evaluated because no blaKPC-positive isolates were identified, and molecular testing remains necessary for confirmatory testing.