MALDI-TOF mass spectrometry (MS) may be used as a rapid typing method for nosocomial pathogens. Here, we evaluated MALDI-TOF MS for discrimination of hospital outbreak-related clusters of Serratia marcescens and carbapenemase-producing Citrobacter freundii. Thirty-three S. marcescens isolates collected from neonatal intensive care unit (NICU) patients, and 23 C. freundii isolates including VIM-positive isolates from a hospital colonization outbreak were measured by Vitek MS. Consensus spectra of each isolate were clustered using SARAMIS software. Genotyping was performed by whole-genome sequencing (WGS). First, a set of 21 S. marcescens isolates from 2014 with seven genotypes including three monoclonal clusters was used for the evaluation of MALDI-TOF typing. MS clustering was largely in agreement with genotyping results when the similarity cut-off for clonal identity was set on 90%. MALDI-TOF cluster analysis was then investigated for the surveillance of S. marcescens in the NICU in 2017 and demonstrated the introduction of new strains into the hospital and nosocomial transmissions. MS analysis of the C. freundii outbreak in 2016 revealed a monoclonal cluster of VIM-positive isolates and the separation of epidemiologically non-related VIM-positive and negative isolates. Two additional VIM-positive Citrobacter isolates from food samples were closely related to the large monoclonal cluster. WGS confirmed the MS results. MALDI-TOF MS may be used as a first-line typing tool for S. marcescens and C. freundii to detect transmission events in the hospital because isolates of an identical WGS type were grouped into the same MS cluster.
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Alzheimers Dement
December 2024
Faculty of Medicine, Oita University, Oita, Japan
Background: Abnormal amyloid‐β (Aβ) deposition in the brain has been defined as the earliest pathological change of Alzheimer disease (AD). Immunoprecipitation coupled with MALDI‐TOF MS (IP‐MS) has previously revealed that APP669–711/Aβ1–42 ratio, Aβ1–40/Aβ1–42 ratio, and a combination of these two biomarkers (a composite biomarker) in human plasma correlates highly with SUVR obtained from amyloid PET. In this work, we investigate the usefulness of plasma Aβ biomarkers at baseline in predicting the conversion to AD dementia.
View Article and Find Full Text PDFAlzheimers Dement
December 2024
Department of Psychiatry, School of Medicine, University of Pittsburgh, Pittsburgh, PA, USA
Background: Amyloid β (Aβ) deposition in the brain is a pathological hallmark of Alzheimer's disease (AD). While immunoprecipitation‐mass spectrometry (IP‐MS) stands out as an accurate method for quantifying blood‐based Aβ peptides, its major limitations such as prolonged sample preparation, extensive analysis time, large specimen volume, and high costs, present opportunities for improvement. Consequently, we aimed to develop a novel plasma IP‐MS Aβ assay that employs simplified and significantly shorter analytical procedures, along with much‐reduced sample volumes.
View Article and Find Full Text PDFAlzheimers Dement
December 2024
Adeptrix Corp, Beverly, MA, USA
Background: The rapidly growing pipeline of target‐specific Alzheimer’s Disease (AD) therapeutic candidates requires accompanying tests that can identify patients likely to have a beneficial response. The growing importance of multiple pathologies in determining AD progression and treatment response underscores this need. Our work focuses on establishing analytical capability to expand detectable forms of major protein drug targets for AD: Tau, amyloid beta (Ab) and a‐Synuclein (aS) proteoforms as potential personalized molecular signatures.
View Article and Find Full Text PDFCarbohydr Polym
March 2025
Glycomics and Glycan Bioengineering Research Center (GGBRC), College of Food Science and Technology, Nanjing Agricultural University, Nanjing 210095, China. Electronic address:
The major hurdle of xenotransplantation is the immune response triggered by human natural antibodies interacting with carbohydrate antigens on the transplanted animal organ. Specifically, terminal glycoprotein motifs such as galactose-α1,3-galactose (α-Gal) and N-glycolylneuraminic acid (Neu5Gc) are significant obstacles. Little is known about the abundance and compositions of asparagine-linked complex carbohydrates (N-glycans) carrying these motifs in mammalian organs.
View Article and Find Full Text PDFAppl Microbiol Biotechnol
January 2025
Vibrio Reference Laboratory, Bureau of Microbial Hazards, Health Canada, Ottawa, ON, Canada.
Two methods were compared for their ability to accurately identify Vibrio species of interest: whole genome sequencing as the reference method and MALDI-TOF MS (matrix-assisted laser desorption/ionization-time of flight mass spectrometry) proteome fingerprinting. The accuracy of mass spectrometry-based identification method was evaluated for its ability to accurately identify isolates of Vibrio cholerae and Vibrio parahaemolyticus. Identification result of each isolate obtained by mass spectrometry was compared to identification by whole genome sequencing (WGS).
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