title: Rapid detection of high-risk Enterococcus faecium clones by matrix-assisted laser desorption ionization time-of-flight mass spectrometry.
abstract: We aimed to explore the potential of matrix assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF MS) for early identification of dominant Enterococcus faecium (Efm) clones involved in human infections. Well-characterized Efm isolates (n=77), analyzed by pulsed-field gel electrophoresis and multilocus sequence typing(eBURST and BAPS [Bayesian analysis of population structure] algorithms), and belonging to different hospital (n=53) and community (n=24) phylogenomic groups, were tested. Mass spectra (Bruker) were analyzed by visual inspection and different chemometric tools. Discrimination between groups comprising isolates commonly found in hospitals (BAPS 2.1a, 3.3a1, 3.3a2) and community (BAPS 2.1b and 3.2) was achieved with >99% accuracy, while identification of sequence types belonging to different BAPS subgroups was associated with >95% correct predictions. Our work is a proof of concept with regard to the suitability of MALDI-TOF MS in the identification of high-risk Efm clones. Further studies including strains from a wider variety of clones and sources will strengthen the potential of the workflow here described.
authors.affiliation: UCIBIO-REQUIMTE, Laboratório de Microbiologia, Departamento de Ciências Biológicas, Faculdade de Farmácia, Universidade do Porto, Porto, Portugal.
authors.forename: Ana R
authors.initials: AR
authors.lastname: Freitas
authors.affiliation: LAQV/REQUIMTE, Departamento de Ciências Químicas, Faculdade de Farmácia, Universidade do Porto, Porto, Portugal.
authors.forename: Clara
authors.initials: C
authors.lastname: Sousa
authors.affiliation: UCIBIO-REQUIMTE, Laboratório de Microbiologia, Departamento de Ciências Biológicas, Faculdade de Farmácia, Universidade do Porto, Porto, Portugal.
authors.forename: Carla
authors.initials: C
authors.lastname: Novais
authors.affiliation: UCIBIO-REQUIMTE, Laboratório de Microbiologia, Departamento de Ciências Biológicas, Faculdade de Farmácia, Universidade do Porto, Porto, Portugal; ESALD, Instituto Politécnico de Castelo Branco, Castelo Branco, Portugal.
authors.forename: Liliana
authors.initials: L
authors.lastname: Silva
authors.affiliation: Serviço de Microbiologia, Centro Hospitalar do Porto, Porto, Portugal.
authors.forename: Helena
authors.initials: H
authors.lastname: Ramos
authors.affiliation: Servicio de Microbiologia, Hospital Universitario Ramón y Cajal and Instituto Ramón and Cajal de Investigación Sanitaria (IRYCIS), Madrid, Spain; CIBER Epidemiología y Salud Pública, Madrid, Spain.
authors.forename: Teresa M
authors.initials: TM
authors.lastname: Coque
authors.affiliation: Research Institute for Medicines (iMed.ULisboa), Faculdade de Farmácia, Universidade de Lisboa, Lisboa, Portugal.
authors.forename: João
authors.initials: J
authors.lastname: Lopes
authors.affiliation: UCIBIO-REQUIMTE, Laboratório de Microbiologia, Departamento de Ciências Biológicas, Faculdade de Farmácia, Universidade do Porto, Porto, Portugal. Electronic address: lpeixe@ff.up.pt.
authors.forename: Luísa
authors.initials: L
authors.lastname: Peixe
mesh_terms: D015373:Bacterial Typing Techniques / Q000379:methods; D001499:Bayes Theorem; D016521:Electrophoresis, Gel, Pulsed-Field / Q000379:methods; D016984:Enterococcus faecium / Q000302:isolation & purification*; D016908:Gram-Positive Bacterial Infections / Q000382:microbiology*; D006801:Humans; D058885:Multilocus Sequence Typing / Q000379:methods; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization / Q000379:methods
keywords: Chemometrics; High-risk clones; MALDI-TOF MS; MLST; Typing; VRE