title: A simple, robust and rapid approach to detect carbapenemases in Gram-negative isolates by MALDI-TOF mass spectrometry: validation with triple quadripole tandem mass spectrometry, microarray and PCR.
abstract: Carbapenemases should be accurately and rapidly detected, given their possible epidemiological spread and their impact on treatment options. Here, we developed a simple, easy and rapid matrix-assisted laser desorption ionization-time of flight (MALDI-TOF)-based assay to detect carbapenemases and compared this innovative test with four other diagnostic approaches on 47 clinical isolates. Tandem mass spectrometry (MS-MS) was also used to determine accurately the amount of antibiotic present in the supernatant after 1 h of incubation and both MALDI-TOF and MS-MS approaches exhibited a 100% sensitivity and a 100% specificity. By comparison, molecular genetic techniques (Check-MDR Carba PCR and Check-MDR CT103 microarray) showed a 90.5% sensitivity and a 100% specificity, as two strains of Aeromonas were not detected because their chromosomal carbapenemase is not targeted by probes used in both kits. Altogether, this innovative MALDI-TOF-based approach that uses a stable 10-μg disk of ertapenem was highly efficient in detecting carbapenemase, with a sensitivity higher than that of PCR and microarray.
authors.affiliation: Institute of Microbiology, University of Lausanne and University Hospital Center, Lausanne, Switzerland.
authors.forename: C
authors.initials: C
authors.lastname: Vogne
authors.forename: G
authors.initials: G
authors.lastname: Prod'hom
authors.forename: K
authors.initials: K
authors.lastname: Jaton
authors.forename: L A
authors.initials: LA
authors.lastname: Decosterd
authors.forename: G
authors.initials: G
authors.lastname: Greub
mesh_terms: D001426:Bacterial Proteins / Q000032:analysis*; D001431:Bacteriological Techniques / Q000379:methods*; D006090:Gram-Negative Bacteria / Q000201:enzymology*; D046228:Microarray Analysis / Q000379:methods; D016133:Polymerase Chain Reaction / Q000379:methods; D012680:Sensitivity and Specificity; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization / Q000379:methods*; D053719:Tandem Mass Spectrometry / Q000379:methods; D001618:beta-Lactamases / Q000032:analysis*
chemical_list: D001426:Bacterial Proteins; D001618:beta-Lactamases; C063912:carbapenemase
keywords: Carbapenem resistance; Gram-negative bacilli; MALDI-TOF MS; MS-MS spectrometry; PCR; microarray