scholarly journals Beyond the Matrix-Assisted Laser Desorption Ionization (MALDI) Biotyping Workflow: in Search of Microorganism-Specific Tryptic Peptides Enabling Discrimination of Subspecies

2014 ◽  
Vol 80 (14) ◽  
pp. 4234-4241 ◽  
Author(s):  
Maria-Theresia Gekenidis ◽  
Patrick Studer ◽  
Simone Wüthrich ◽  
René Brunisholz ◽  
David Drissner
Keyword(s):  
Mass Spectrometry ◽  
Laser Desorption ◽  
Clinical Diagnostics ◽  
Laser Desorption Ionization ◽  
Accurate Identification ◽  
Discrimination Power ◽  
Desorption Ionization ◽  
Maldi Tof ◽  
Matrix Assisted Laser ◽  
Matrix Assisted Laser Desorption

ABSTRACTA well-accepted method for identification of microorganisms uses matrix-assisted laser desorption ionization–time of flight mass spectrometry (MALDI-TOF MS) coupled to analysis software which identifies and classifies the organism according to its ribosomal protein spectral profile. The method, called MALDI biotyping, is widely used in clinical diagnostics and has partly replaced conventional microbiological techniques such as biochemical identification due to its shorter time to result (minutes for MALDI biotyping versus hours or days for classical phenotypic or genotypic identification). Besides its utility for identifying bacteria, MS-based identification has been shown to be applicable also to yeasts and molds. A limitation to this method, however, is that accurate identification is most reliably achieved on the species level on the basis of reference mass spectra, making further phylogenetic classification unreliable. Here, it is shown that combining tryptic digestion of the acid/organic solvent extracted (classical biotyping preparation) and resolubilized proteins, nano-liquid chromatography (nano-LC), and subsequent identification of the peptides by MALDI-tandem TOF (MALDI-TOF/TOF) mass spectrometry increases the discrimination power to the level of subspecies. As a proof of concept, using this targeted proteomics workflow, we have identified subspecies-specific biomarker peptides for threeSalmonellasubspecies, resulting in an extension of the mass range and type of proteins investigated compared to classical MALDI biotyping. This method therefore offers rapid and cost-effective identification and classification of microorganisms at a deeper taxonomic level.

scholarly journals Rapid and Robust Identification of the Agents of Black-Grain Mycetoma by Matrix-Assisted Laser Desorption Ionization–Time of Flight Mass Spectrometry

2017 ◽  
Vol 55 (8) ◽  
pp. 2521-2528 ◽  
Author(s):  
Mark Fraser ◽  
Andrew M. Borman ◽  
Elizabeth M. Johnson
Keyword(s):  
Mass Spectrometry ◽  
Laser Desorption ◽  
Laser Desorption Ionization ◽  
Accurate Identification ◽  
Ionization Time ◽  
Content Type ◽  
Desorption Ionization ◽  
Maldi Tof ◽  
Matrix Assisted Laser ◽  
Matrix Assisted Laser Desorption

ABSTRACTEumycetoma, a chronic fungal infection endemic in India, Indonesia, and parts of Africa and South and Central America, follows traumatic implantation of saprophytic fungi and frequently requires radical surgery or amputation in the absence of appropriate treatment. Fungal species that can cause black-grain mycetomas includeMadurellaspp.,Falciformisporaspp.,Trematosphaeria grisea,Nigrograna mackinnonii,Pseudochaetosphaeronema larense,Medicopsis romeroi, andEmarelliaspp.Rhytidhysteron rufulumandParathyridaria percutaneacause similar subcutaneous infections, but these infections lack the draining sinuses and fungal grains characteristic of eumycetoma. Accurate identification of the agents of subcutaneous fungal infection is essential to guide appropriate antifungal therapy. Since phenotypic identification of the causative fungi is often difficult, time-consuming molecular approaches are currently required. In the study described here we evaluated whether matrix-assisted laser desorption ionization–time of flight (MALDI-TOF) mass spectrometry might allow the accurate identification of eumycetoma agents and related fungi. A panel of 57 organisms corresponding to 10 different species from confirmed cases of eumycetoma and subcutaneous pedal masses, previously formally identified by PCR amplification and sequencing of internal transcribed spacer 1 (ITS1), was employed. Representative isolates of each species were used to create reference MALDI-TOF spectra, which were then used for the identification of the remaining isolates in a user-blinded manner. Here, we demonstrate that MALDI-TOF mass spectrometry accurately identified all of the test isolates, with 100%, 90.4%, and 67.3% of isolates achieving log scores greater than 1.8, 1.9, and 2.0, respectively.

scholarly journals Performance of Matrix-Assisted Laser Desorption Ionization–Time of Flight Mass Spectrometry for Identifying Clinical Malassezia Isolates

2016 ◽  
Vol 55 (1) ◽  
pp. 90-96 ◽  
Author(s):  
Julie Denis ◽  
Marie Machouart ◽  
Florent Morio ◽  
Marcela Sabou ◽  
Catherine Kauffmann-LaCroix ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
Time Of Flight ◽  
Laser Desorption ◽  
Laser Desorption Ionization ◽  
Ionization Time ◽  
Content Type ◽  
Desorption Ionization ◽  
Maldi Tof ◽  
Matrix Assisted Laser ◽  
Matrix Assisted Laser Desorption

ABSTRACT The genus Malassezia comprises commensal yeasts on human skin. These yeasts are involved in superficial infections but are also isolated in deeper infections, such as fungemia, particularly in certain at-risk patients, such as neonates or patients with parenteral nutrition catheters. Very little is known about Malassezia epidemiology and virulence. This is due mainly to the difficulty of distinguishing species. Currently, species identification is based on morphological and biochemical characteristics. Only molecular biology techniques identify species with certainty, but they are time-consuming and expensive. The aim of this study was to develop and evaluate a matrix-assisted laser desorption ionization–time of flight (MALDI-TOF) database for identifying Malassezia species by mass spectrometry. Eighty-five Malassezia isolates from patients in three French university hospitals were investigated. Each strain was identified by internal transcribed spacer sequencing. Forty-five strains of the six species Malassezia furfur , M. sympodialis , M. slooffiae , M. globosa , M. restricta , and M. pachydermatis allowed the creation of a MALDI-TOF database. Forty other strains were used to test this database. All strains were identified by our Malassezia database with log scores of >2.0, according to the manufacturer's criteria. Repeatability and reproducibility tests showed a coefficient of variation of the log score values of <10%. In conclusion, our new Malassezia database allows easy, fast, and reliable identification of Malassezia species. Implementation of this database will contribute to a better, more rapid identification of Malassezia species and will be helpful in gaining a better understanding of their epidemiology.

scholarly journals An improved simple method for the identification of Mycobacteria by MALDI-TOF MS (Matrix-Assisted Laser Desorption- Ionization mass spectrometry)

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Adela Alcolea-Medina ◽  
M. T. Cabezas Fernandez ◽  
N. Montiel ◽  
M. P. Luzón García ◽  
C. Delamo Sevilla ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
Laser Desorption ◽  
Ionization Mass ◽  
Laser Desorption Ionization ◽  
Isolation And Identification ◽  
Simple Method ◽  
Desorption Ionization ◽  
Maldi Tof ◽  
Matrix Assisted Laser ◽  
Matrix Assisted Laser Desorption

AbstractThe aim of this study was to establish a simple method for the rapid identification of Mycobacteria species by MALDI-TOF (Matrix-Assisted Laser Desorption/Ionization-Time of Flight Mass spectrometry) using the Bruker MALDI-TOF Biotyper system (Bruker Daltonik, Bremen, Germany). A multicentre, prospective, and single blind study was performed in three European Hospitals, two Spanish and one UK hospital from May to August 2018. The BD BACTEC MGIT (Becton Dickinson, Berks, UK) liquid culture system was used in all three centres for the growth of Mycobacteria. When signal positive, tubes were removed from the analyser and in addition to standard laboratory procedures were subcultured on blood agar plates for MALDI-TOF analysis. Plates were incubated aerobically for 1 to 7 days at 37 °C and inspected every day. Once any growth was visible, it was transferred to the steel target plate, overlaid with 1 μl of neat formic acid and 1 μl HCCA matrix (alpha hydroxyl 4 cinnamic acid), and analysed in a Bruker Biotyper MALDI-TOF. Results given by MALDI-TOF were compared with the reference methods used for identification in the different centres. At two Spanish hospitals, identification by MALDI-TOF was only attempted on presumptive non-tuberculosis mycobacteria (NTM) and the results were initially compared with the results obtained by a commercial reverse hybridisation assay, GenoType CM/AS (Hain Lifescience, Tübingen, Germany). At the UK Hospital, identification of any presumptive mycobacteria was attempted and compared with the results obtained by whole genome sequencing (WGS). Overall in 142/167 (85%) of cases the identifications obtained were concordant; all Mycobacterium tuberculosis (MTB) isolates 43/43 (100%), 57/76 (75%) of the rapid growing nontuberculous mycobacteria (NTM), and 42/48 (85%) slow growing NTM tested were identified correctly. We report a new, easy, cheap and quick method for isolation and identification of Mycobacterium spp. without the need for additional steps or equipment and this method is in routine used in all three centres.

scholarly journals Uncatalyzed reactions of 4,4′-diphenylmethane-diisocyanate with polymer polyols as revealed by matrix-assisted laser desorption/ionization mass spectrometry

RSC Advances ◽  
2016 ◽  
Vol 6 (52) ◽  
pp. 47023-47032 ◽  
Author(s):  
Tibor Nagy ◽  
Borbála Antal ◽  
Anita Dékány-Adamoczky ◽  
József Karger-Kocsis ◽  
Miklós Zsuga ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
Laser Desorption ◽  
Ionization Mass ◽  
Diphenylmethane Diisocyanate ◽  
Laser Desorption Ionization ◽  
Maldi Tof Mass Spectrometry ◽  
Desorption Ionization ◽  
Maldi Tof ◽  
Matrix Assisted Laser ◽  
Matrix Assisted Laser Desorption

The reactivities of various polymer polyols towards MDI were evaluated using MALDI-TOF mass spectrometry.

Can Matrix-Assisted Laser Desorption Ionization Time-of-Flight Mass Spectrometry (MALDI-TOF) Enhance Antimicrobial Stewardship Efforts in the Acute Care Setting?

2013 ◽  
Vol 34 (9) ◽  
pp. 990-995 ◽  
Author(s):  
Pranita D. Tamma ◽  
Kennard Tan ◽  
Veronique R. Nussenblatt ◽  
Alison E. Turnbull ◽  
Karen C. Carroll ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
Time Of Flight ◽  
Laser Desorption ◽  
Laser Desorption Ionization ◽  
Ionization Time ◽  
Desorption Ionization ◽  
Maldi Tof ◽  
Flight Mass Spectrometry ◽  
Matrix Assisted Laser ◽  
Matrix Assisted Laser Desorption

We evaluated 222 hospitalized patients whose clinical isolates were tested using standard methods and matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF). MALDI-TOF could have reduced time to appropriate therapy for 28.8% and 44.6% patients based on the treating physician's choices and stewardship team recommendations, respectively. Clinicians should be aware of scenarios in which MALDI-TOF can optimize antibiotic therapy.

scholarly journals Peaks of Promise and Peril: Screening for Antibiotic Resistance by Matrix-Assisted Laser Desorption Ionization–Time of Flight Mass Spectrometry

2015 ◽  
Vol 54 (1) ◽  
pp. 5-6 ◽  
Author(s):  
Neil W. Anderson
Keyword(s):  
Mass Spectrometry ◽  
Time Of Flight ◽  
Laser Desorption ◽  
Laser Desorption Ionization ◽  
Ionization Time ◽  
Maldi Tof Mass Spectrometry ◽  
Desorption Ionization ◽  
Maldi Tof ◽  
Matrix Assisted Laser ◽  
Matrix Assisted Laser Desorption

An article in this issue of theJournal of Clinical Microbiology(J.-H. Youn, S. K. Drake, R. A. Weingarten, K. M. Frank, J. P. Dekker, and A. F. Lau, J Clin Microbiol 53:35–42, 2015,http://dx.doi.org/10.1128/JCM.01643-15) describes the use of matrix-assisted laser desorption ionization–time of flight (MALDI-TOF) mass spectrometry for the detection of organisms carrying ablaKPC-containing plasmid. This powerful and promising application highlights the challenges of using MALDI-TOF mass spectrometry for purposes other than organism identification.

scholarly journals Effect of Culture Conditions on Microorganism Identification by Matrix-Assisted Laser Desorption Ionization Mass Spectrometry

2005 ◽  
Vol 71 (1) ◽  
pp. 58-64 ◽  
Author(s):  
Nancy Valentine ◽  
Sharon Wunschel ◽  
David Wunschel ◽  
Catherine Petersen ◽  
Karen Wahl
Keyword(s):  
Mass Spectrometry ◽  
Laser Desorption ◽  
Ionization Mass ◽  
Laser Desorption Ionization ◽  
Maldi Tof Ms ◽  
Desorption Ionization ◽  
Maldi Tof ◽  
Tof Ms ◽  
Matrix Assisted Laser ◽  
Matrix Assisted Laser Desorption

ABSTRACT Matrix-assisted laser desorption ionization-time-of-flight mass spectrometry (MALDI-TOF MS) has been used to identify bacteria based upon protein signatures. This research shows that while some different proteins are produced by vegetative bacteria when they are cultured in different growth media, positive identification with MALDI-TOF MS is still possible with the protocol established at the Pacific Northwest National Laboratory (K. H. Jarman, S. T. Cebula, A. J. Saenz, C. E. Petersen, N. B. Valentine, M. T. Kingsley, and K. L. Wahl, Anal. Chem. 72:1217-1223, 2000). A core set of small proteins remain constant under at least four different culture media conditions and blood agar plates, including minimal medium M9, rich media, tryptic soy broth (TSB) or Luria-Bertani (LB) broth, and blood agar plates, such that analysis of the intact cells by matrix-assisted laser desorption/ionization mass spectrometry allows for consistent identification.

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