Methodology Comparison of Multiple Phenotypic and Genotypic Tests in Carbapenem-Resistant <i>Klebsiella pneumoniae</i>

Abstract

Background: Swift and accurate identification of carbapenemase variants is essential for optimizing clinical outcomes and patient prognosis. Objectives: This study conducted a retrospective analysis to compare six methods for detecting carbapenem-resistant Klebsiella pneumoniae (CRKP) strains collected from 2016 to 2023, using polymerase chain reaction (PCR) sequencing as the reference standard. Methods: A total of 88 CRKP strains were selected to detect the expression of carbapenem resistance genes via PCR. The PCR assay results were used as the gold standard to compare the effectiveness of six other assays, including the modified carbapenem inactivation method (mCIM), EDTA-modified carbapenem inactivation method (eCIM), simplified carbapenem inactivation method (sCIM), simple EDTA synergistic carbapenem inactivation method (esCIM), colloidal gold method, and GeneXpert Carba-R. Results: PCR identified 85 CRKP strains as positive for carbapenem-resistant genes. In comparison, GeneXpert Carba-R exhibited the best diagnostic performance (sensitivity = 97.65%, specificity = 100.00%, kappa = 0.945), followed by the colloidal gold method (sensitivity = 96.47%, specificity = 100.00%, kappa = 0.923). Conclusions: GeneXpert Carba-R's simplicity and rapidity facilitate pharmaceutical optimization and enhance clinical efficacy. Although the colloidal gold method demonstrates slightly lower sensitivity and specificity compared to GeneXpert Carba-R, its cost-effectiveness and lack of specialized equipment make it suitable for primary healthcare settings.