Evaluation of the Bruker MALDI Biotyper (MBT) subtyping module for detection of <i>Klebsiella pneumoniae</i> carbapenemase (KPC) in <i>Enterobacterales</i> in a Canadian clinical microbiology laboratory

<i>Enterobacterales</i>, a large order of pathogenic and commensal bacteria, can gain resistance to carbapenems through the acquisition of plasmids carrying genes, such as <i>Klebsiella pneumoniae</i> carbapenemase (KPC). Early detection of KPC is crucial for patient care; however, current detection methods that involve multiple time-consuming steps, commonly only undertaken after overnight susceptibility testing, indicate possible carbapenem resistance. This study examined the ability of matrix-assisted laser desorption/ionization time-of-flight (MALDI-ToF), a common diagnostic tool in the clinical laboratory, to detect KPC among <i>Enterobacterales</i>. KPC detection via MALDI-ToF had low sensitivity but 100% specificity. These results support and expand the microbiological and geographical range of prior publications for this tool. A practical application of this highly specific method would involve rapid triaging of KPC-positive isolates a day earlier than current methods, permitting initiation of more timely therapeutic and infection prevention and control measures.