title: Evaluation of a modified meropenem hydrolysis assay on a large cohort of KPC and VIM carbapenemase-producing Enterobacteriaceae.
abstract: Carbapenem-resistant Enterobacteriaceae (CRE) have spread globally and represent a serious and growing threat to public health. The introduction of rapid and sensitive methods for the detection of carbapenemase-producing bacteria is of increasing importance. The carbapenemase production can be detected using non-molecular methods (such as the modified Hodge test, the synergy test, the Carba NP test and the antibiotic hydrolysis assays) and DNA-based methods. In this study, we propose a modified version of a previously described meropenem hydrolysis assay (MHA) by MALDI-TOF MS for the phenotypic detection in 2h of carbapenemase-producing Enterobacteriaceae. The MHA was successfully applied to detect carbapenemase activity in 981 well-characterized Enterobacteriaceae strains producing KPC or VIM carbapenemases, and in 146 carbapenem fully susceptible strains. This assay, applied also to NDM and OXA-48-producing strains and to CRE with resistance mechanisms other than carbapenemase production, has proved to be able to distinguish between carbapenemase-producing and -nonproducing Enterobacteriaceae. As already stated and as observed in our hands, MHA by MALDI-TOF MS analysis is independent from the type of carbapenemases involved, it is faster and easier to perform/interpret than culture-based methods. On the other hand, it cannot detect other carbapenem resistance mechanisms, such as porin alterations and efflux mechanisms.
authors.affiliation: Unit of Microbiology and Virology, Department of Clinical and Experimental Medicine, University of Parma, Parma, Italy.
authors.forename: Adriana
authors.initials: A
authors.lastname: Calderaro
authors.affiliation: Unit of Microbiology and Virology, Department of Clinical and Experimental Medicine, University of Parma, Parma, Italy.
authors.forename: Mirko
authors.initials: M
authors.lastname: Buttrini
authors.affiliation: Unit of Microbiology and Virology, Department of Clinical and Experimental Medicine, University of Parma, Parma, Italy.
authors.forename: Maddalena
authors.initials: M
authors.lastname: Piergianni
authors.affiliation: Unit of Microbiology and Virology, Department of Clinical and Experimental Medicine, University of Parma, Parma, Italy.
authors.forename: Sara
authors.initials: S
authors.lastname: Montecchini
authors.affiliation: Unit of Microbiology and Virology, Department of Clinical and Experimental Medicine, University of Parma, Parma, Italy.
authors.forename: Monica
authors.initials: M
authors.lastname: Martinelli
authors.affiliation: Unit of Microbiology and Virology, Department of Clinical and Experimental Medicine, University of Parma, Parma, Italy.
authors.forename: Silvia
authors.initials: S
authors.lastname: Covan
authors.affiliation: Unit of Microbiology and Virology, Department of Clinical and Experimental Medicine, University of Parma, Parma, Italy.
authors.forename: Giovanna
authors.initials: G
authors.lastname: Piccolo
authors.affiliation: Unit of Microbiology and Virology, Department of Clinical and Experimental Medicine, University of Parma, Parma, Italy.
authors.forename: Maria Cristina
authors.initials: MC
authors.lastname: Medici
authors.affiliation: Unit of Microbiology and Virology, Department of Clinical and Experimental Medicine, University of Parma, Parma, Italy.
authors.forename: Maria Cristina
authors.initials: MC
authors.lastname: Arcangeletti
authors.affiliation: Unit of Microbiology and Virology, Department of Clinical and Experimental Medicine, University of Parma, Parma, Italy.
authors.forename: Carlo
authors.initials: C
authors.lastname: Chezzi
authors.affiliation: Unit of Microbiology and Virology, Department of Clinical and Experimental Medicine, University of Parma, Parma, Italy.
authors.forename: Flora
authors.initials: F
authors.lastname: De Conto
mesh_terms: D001426:Bacterial Proteins / Q000096:biosynthesis*; D004755:Enterobacteriaceae / Q000187:drug effects* / Q000201:enzymology; D000077731:Meropenem; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization; D013845:Thienamycins / Q000378:metabolism* / Q000494:pharmacology; D001618:beta-Lactamases / Q000096:biosynthesis*
chemical_list: D001426:Bacterial Proteins; D013845:Thienamycins; D001618:beta-Lactamases; C063912:carbapenemase; D000077731:Meropenem