Enferm Infecc Microbiol Clin. 2021 Apr 15:S0213-005X(21)00082-3. doi: 10.1016/j.eimc.2021.03.013. Online ahead of print.
INTRODUCTION: Here, we propose a novel modified Carba NP test for detecting KPC-producing Enterobacterales using imipenem/relebactam.
MATERIAL AND METHODS: The test performance was evaluated in a random selection of 160 previously molecularly characterized clinical isolates carrying the 110 blaKPC, 1 blaGES, 12 blaVIM, 4 blaIMP, 3 blaNDM and 42 blaOXA-48-like genes. The proposed method relies on the detection of imipenem hydrolysis in an imipenem/relebactam antibiotic solution and subsequent visual interpretation by color change.
RESULTS: All class A producing Enterobacterales (111/111) were detected using imipenem/relebactam as no visual appreciation of color change was perceived due to a nule hydrolysis of imipenem in the antibiotic solution. Overall, the assay showed 100% sensitivity (111/111) and specificity (69/69) for detecting class A KPC-producing Enterobacterales.
DISCUSSION: The biochemical assay provides very reliable results for detecting KPC-producing Enterobacterales, with a turnaround time of less than 1 hour, minimum handling and no specialized equipment required.