Rapid detection of carbapenemases in multiresistant Gram-negative strains: evaluation of two tests

Carbapenem-resistant organisms (CRO) have rapidly spread worldwide in recent years, posing a significant challenge to both human health and healthcare systems. Timely and accurate detection of CRO, especially carbapenemase-producing Enterobacterales and non-fermenters, is crucial for clinical prevention and treatment of these infections. In the present study, we subjected more than 114 multidrug-resistant Gram-negative Enterobacterales and non-fermenters to two tests for the timely detection of carbapenemases. The strains were exclusively clinical isolates, and they were examined using both the CARBA-5 (NG Biotech) test and the molecular genetic analysis via the Allplex Entero-DR assay (Seegene). The NG CARBA-5 test exhibited a sensitivity of 63.2% (72/114), whereas the Allplex Entero-DR assay achieved a sensitivity of 71.9% (82/114). In both tests, it was primarily non-fermenters-A. baumannii (11/13 84.62%) and P. aeruginosa (11/21 52.38%)-in which the test did not detect any carbapenemase. Moreover, direct PCR-based detection of carbapenemases from the primary swab tube was successful in 12 out of 12 samples. This investigation highlighted that there is room for improvement in sensitivity when performing multiplex lateral flow immunochromatographic assays, as well as PCR-based methods. The direct detection of carbapenemases in primary swab tubes represents a broadly applicable approach for future molecular genetic testing methods.IMPORTANCERapid and accurate detection of carbapenemase-producing bacteria is essential for infection control and effective treatment, especially as antimicrobial resistance continues to rise worldwide. Carbapenem-resistant Gram-negative pathogens, including Enterobacterales and non-fermenters, are particularly challenging due to limited therapeutic options and high transmission risk in healthcare settings. This study evaluates two diagnostic approaches-a lateral flow assay and a PCR-based molecular test-for detecting key carbapenemase genes. By comparing their performance in over 100 multidrug-resistant clinical isolates, the study provides practical insights into the sensitivity and limitations of each method. Importantly, it demonstrates that direct PCR testing from primary patient material is feasible and yields reliable results. These findings support the use of molecular diagnostics for early resistance detection and help inform clinical decision-making and infection control strategies. The results are especially relevant for microbiology laboratories aiming to improve diagnostic workflows and enhance preparedness against resistant pathogens.