scholarly journals A Moldy Application of MALDI: MALDI-ToF Mass Spectrometry for Fungal Identification

2019 ◽  
Vol 5 (1) ◽  
pp. 4 ◽  
Author(s):  
Robin Patel
Keyword(s):  
Mass Spectrometry ◽  
Filamentous Fungi ◽  
Bacterial Identification ◽  
Ionization Time ◽  
Maldi Tof Ms ◽  
Maldi Tof ◽  
Flight Mass Spectrometry ◽  
Fungal Identification ◽  
Routine Identification ◽  
Tof Ms

As a result of its being inexpensive, easy to perform, fast and accurate, matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-ToF MS) is quickly becoming the standard means of bacterial identification from cultures in clinical microbiology laboratories. Its adoption for routine identification of yeasts and even dimorphic and filamentous fungi in cultures, while slower, is now being realized, with many of the same benefits as have been recognized on the bacterial side. In this review, the use of MALDI-ToF MS for identification of yeasts, and dimorphic and filamentous fungi grown in culture will be reviewed, with strengths and limitations addressed.

scholarly journals Matrix-Assisted Laser Desorption Ionization-Time of Flight Mass Spectrometry (MALDI-TOF MS) Applications in Bacteriology: brazilian contributions

HU Revista ◽  
2018 ◽  
Vol 43 (3) ◽  
pp. 285-294
Author(s):  
Flávia Lúcia Piffano Costa Pellegrino ◽  
Thiago Pavoni Gomes Chagas ◽  
Maria Silvana Alves ◽  
Ana Paula D’Alincourt Carvalho-Assef ◽  
Alexander Chapeaurouge ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
Laser Desorption ◽  
Bacterial Identification ◽  
Laser Desorption Ionization ◽  
Ionization Time ◽  
Maldi Tof Ms ◽  
Maldi Tof ◽  
Flight Mass Spectrometry ◽  
Tof Ms ◽  
Matrix Assisted Laser

Among its innumerous applications in Bacteriology, the Matrix-Assisted Laser Desorption Ionization-Time of Flight Mass Spectrometry (MALDI-TOF MS) technique is evolving as a powerful tool for bacterial identification and antimicrobial resistance investigation. Publications have evaluated the MALDI-TOF MS performance in the identification of a series of bacterial pathogens, including the most common severe infectious agents, emergent pathogens involved with outbreaks of healthcare-associated infections, rare pathogens, and those whose isolation in culture media is difficult. As compared to conventional methods of bacterial identification, MALDI-TOF MS has proven to be a fast, accurate and cost-effective technique. Currently, MALDI-TOF MS has been used in antimicrobial resistance studies, since it has shown to be an efficient tool in detecting specific resistance mechanisms in bacteria, such as beta-lactamases production, for example. Here, we describe the advances in this growing field of mass spectrometry applied to Bacteriology, including Brazilian contributions.

scholarly journals Application of MALDI-TOF mass spectrometry in clinical diagnostic microbiology

2014 ◽  
Vol 8 (09) ◽  
pp. 1081-1088 ◽  
Author(s):  
Elena De Carolis ◽  
Antonietta Vella ◽  
Luisa Vaccaro ◽  
Riccardo Torelli ◽  
Teresa Spanu ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
Drug Susceptibility ◽  
Biochemical Tests ◽  
Ionization Time ◽  
Maldi Tof Ms ◽  
Maldi Tof ◽  
Flight Mass Spectrometry ◽  
Bacteria And Fungi ◽  
Diagnostic Microbiology ◽  
Tof Ms

Matrix-assisted laser desorption/ionization-time of flight mass spectrometry (MALDI-TOF MS) has recently emerged as a powerful technique for identification of microorganisms, changing the workflow of well-established laboratories so that its impact on microbiological diagnostics has been unparalleled. In comparison with conventional identification methods that rely on biochemical tests and require long incubation procedures, MALDI-TOF MS has the advantage of identifying bacteria and fungi directly from colonies grown on culture plates in a few minutes and with simple procedures. Numerous studies on different systems available demonstrate the reliability and accuracy of the method, and new frontiers have been explored besides microbial species level identification, such as direct identification of pathogens from positive blood cultures, subtyping, and drug susceptibility detection.

scholarly journals Current Status of Matrix-Assisted Laser Desorption/Ionization–Time-of-Flight Mass Spectrometry (MALDI-TOF MS) in Clinical Diagnostic Microbiology

Molecules ◽  
2020 ◽  
Vol 25 (20) ◽  
pp. 4775
Author(s):  
Sachio Tsuchida ◽  
Hiroshi Umemura ◽  
Tomohiro Nakayama
Keyword(s):  
Mass Spectrometry ◽  
Laser Desorption ◽  
Clinical Applications ◽  
Laser Desorption Ionization ◽  
Ionization Time ◽  
Maldi Tof Ms ◽  
Maldi Tof ◽  
Flight Mass Spectrometry ◽  
Tof Ms ◽  
Matrix Assisted Laser

Mass spectrometry (MS), a core technology for proteomics and metabolomics, is currently being developed for clinical applications. The identification of microorganisms in clinical samples using matrix-assisted laser desorption/ionization–time-of-flight mass spectrometry (MALDI-TOF MS) is a representative MS-based proteomics application that is relevant to daily clinical practice. This technology has the advantages of convenience, speed, and accuracy when compared with conventional biochemical methods. MALDI-TOF MS can shorten the time used for microbial identification by about 1 day in routine workflows. Sample preparation from microbial colonies has been improved, increasing the accuracy and speed of identification. MALDI-TOF MS is also used for testing blood, cerebrospinal fluid, and urine, because it can directly identify the microorganisms in these liquid samples without prior culture or subculture. Thus, MALDI-TOF MS has the potential to improve patient prognosis and decrease the length of hospitalization and is therefore currently considered an essential tool in clinical microbiology. Furthermore, MALDI-TOF MS is currently being combined with other technologies, such as flow cytometry, to expand the scope of clinical applications.

scholarly journals Iodine-Assisted Laser Desorption/Ionization Time-of-Flight Mass Spectrometry

2021 ◽  
Vol 4 (1) ◽  
Author(s):  
Sai Raghuveer Chava
Keyword(s):  
Mass Spectrometry ◽  
Time Of Flight ◽  
Laser Desorption ◽  
Laser Desorption Ionization ◽  
Ionization Time ◽  
Maldi Tof Ms ◽  
Desorption Ionization ◽  
Maldi Tof ◽  
Flight Mass Spectrometry ◽  
Tof Ms

Adsorption and desorption of iodine-containing α-cyano-4-hydroxycinnamic acid (aCCa) matrix species were studied using matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS). The MALDI-TOF MS method showed that ca. 0.8- 1.4 monolayer (~ 100 ppm) of iodine-containing species was adsorbed at the surface and assisted in desorption and ionization of a protein digest peptides or peptides varying in isoelectric potential. At low laser power, desorption of analytes in protonated and sodiated form was observed but not iodine cluster relative to aCCa without iodine, suggesting a two-electron reduction process to form the protonated pseudo molecular ion, although adsorption on the surface would lead to oxidation of iodide to iodine. The addition of iodine to matrix has been demonstrated to greatly facilitate the MALDI-TOF MS process and is a valuable tool when complex protein mixtures need to be analyzed.

scholarly journals Species Identification and Delineation of Pathogenic Mucorales by Matrix-Assisted Laser Desorption Ionization–Time of Flight Mass Spectrometry

2018 ◽  
Vol 56 (4) ◽  
pp. e01886-17 ◽  
Author(s):  
Jin Shao ◽  
Zhe Wan ◽  
Ruoyu Li ◽  
Jin Yu
Keyword(s):  
Filamentous Fungi ◽  
Laser Desorption ◽  
Laser Desorption Ionization ◽  
Ionization Time ◽  
Content Type ◽  
Maldi Tof Ms ◽  
Maldi Tof ◽  
Flight Mass Spectrometry ◽  
Reference Strains ◽  
Tof Ms

ABSTRACT This study aimed to validate the effectiveness of matrix-assisted laser desorption ionization–time of flight mass spectrometry (MALDI-TOF MS)-based identification of filamentous fungi of the order Mucorales. A total of 111 isolates covering six genera preserved at the Research Center for Medical Mycology of Peking University were selected for MALDI-TOF MS analysis. We emphasized the study of 23 strains of Mucor irregularis predominantly isolated from patients in China. We first used the Bruker Filamentous Fungi library (v1.0) to identify all 111 isolates. To increase the identification rate, we created a compensatory in-house database, the Beijing Medical University (BMU) database, using 13 reference strains covering 6 species, including M. irregularis, Mucor hiemalis, Mucor racemosus, Cunninghamella bertholletiae, Cunninghamella phaeospora, and Cunninghamella echinulata. All 111 isolates were then identified by MALDI-TOF MS using a combination of the Bruker library and BMU database. MALDI-TOF MS identified 55 (49.5%) and 74 (66.7%) isolates at the species and genus levels, respectively, using the Bruker Filamentous Fungi library v1.0 alone. A combination of the Bruker library and BMU database allowed MALDI-TOF MS to identify 90 (81.1%) and 111 (100%) isolates at the species and genus levels, respectively, with a significantly increased accuracy rate. MALDI-TOF MS poorly identified Mucorales when the Bruker library was used alone due to its lack of some fungal species. In contrast, this technique perfectly identified M. irregularis after main spectrum profiles (MSPs) of relevant reference strains were added to the Bruker library. With an expanded Bruker library, MALDI-TOF MS is an effective tool for the identification of pathogenic Mucorales.

scholarly journals Intact Staphylococcus Enterotoxin SEB from Culture Supernatant Detected by MALDI-TOF Mass Spectrometry

Toxins ◽  
2019 ◽  
Vol 11 (2) ◽  
pp. 101 ◽  
Author(s):  
Jenna Tonacini ◽  
Dario Stephan ◽  
Guido Vogel ◽  
Marc-André Avondet ◽  
Franka Kalman ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
Culture Supernatant ◽  
Main Peak ◽  
Amino Acid Sequence Analysis ◽  
Maldi Tof Ms ◽  
Maldi Tof ◽  
Flight Mass Spectrometry ◽  
Routine Identification ◽  
Intracellular Proteins ◽  
Tof Ms

Routine identification of pathogens by MALDI-TOF MS (matrix-assisted laser desorption ionisation time-of-flight mass spectrometry) is based on the fingerprint of intracellular proteins. This work evaluated the use of MALDI-TOF MS for the identification of extracellular pathogen factors. A Staphylococcus aureus isolate from a food contaminant was exponentially grown in liquid cultures. Secreted proteins were collected using methanol– chloroform precipitation and analysed by MALDI-TOF MS. A main peak m/z 28,250 was demonstrated, which was identified as S.aureus enterotoxin type B (SEB) by using the pure authentic SEB reference of 28.2 kDa and by amino acid sequence analysis. SEB was also detected in this intact form following pasteurization and cooking treatments. Further application of the elaborated MALDI-TOF MS protocol resulted in the detection of SEA at m/z 27,032 and SEC at m/z 27,629. In conclusion, a simple sample preparation from S.aureus cultures and an easy-to-perform identification of pathogen factors SE in intact form represents a promising next-generation application of MALDI-TOF MS.

scholarly journals Use of matrix-assisted laser desorption ionization time-of-flight mass spectrometry analysis of serum peptidome to classify and predict COVID-19 severity

2021 ◽  
Author(s):  
Rosa M Gomila ◽  
Gabriel Martorell ◽  
Pablo A Fraile-Ribot ◽  
Antonio Doménech-Sánchez ◽  
Miguel Albertí ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
Laser Desorption ◽  
Laser Desorption Ionization ◽  
Ionization Time ◽  
Maldi Tof Ms ◽  
Maldi Tof ◽  
Flight Mass Spectrometry ◽  
Critical Patients ◽  
Tof Ms ◽  
Matrix Assisted Laser

Abstract Background Classification and early detection of severe COVID-19 patients is required to establish an effective treatment. We tested the utility of matrix assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) to classify and predict the severity of COVID-19. Methods We used MALDI-TOF MS to analyse the serum peptidome from 72 COVID-19 patients (training cohort), clinically classified as mild (28), severe (23) and critical (21), and 20 healthy controls. The resulting matrix of peak intensities was used for Machine Learning (ML) approaches to classify and predict COVID-19 severity of 22 independent patients (validation cohort). Finally, we analysed all sera by liquid chromatography mass spectrometry (LC MS/MS) to identify the most relevant proteins associated to disease severity. Results We found a clear variability of the serum peptidome profile depending on COVID-19 severity. Forty-two peaks exhibited a log fold change ≥ 1 and 17 were significantly different and at least four-fold more intense in the set of critical patients than in the mild ones. ML approach classified clinical stable patients according to their severity with a 100% of accuracy and predicted correctly the evolution of the non-stable patients in all cases. LC MS/MS identified five proteins that were significantly upregulated in the critical patients. They included the serum amyloid protein A2, which probably yielded the most intense peak detected by MALDI-TOF MS. Conclusion We demonstrated the potential of the MALDI-TOF MS as a bench to bedside technology to aid clinicians in their decisions on COVID-19 patients.

scholarly journals Τυποποίηση στελεχών Legionella Pneumophila από περιβαλλοντικά δείγματα και συρροές κρουσμάτων με Matrix assisted laser desortion ionization Time-of-Flight Mass Spectrometry (ΜALDI-TΟF MS)

2019 ◽  
Author(s):  
Μαρία Κυρίτση
Keyword(s):  
Mass Spectrometry ◽  
Monoclonal Antibodies ◽  
Legionella Pneumophila ◽  
Time Of Flight ◽  
Ionization Time ◽  
Maldi Tof Ms ◽  
Maldi Tof ◽  
Flight Mass Spectrometry ◽  
Tof Ms ◽  
Matrix Assisted Laser

Η εκτίμηση κινδύνου και η πρόληψη της Νόσου των Λεγεωναρίων βασίζονται κυρίως στην ανίχνευση του μικροοργανισμού σε δείγματα νερού. Νόσο στον άνθρωπο προκαλεί κυρίως η Legionella pneumophila οροτύπου 1 (Lp1) και ιδιαίτερα στελέχη τα οποία φέρουν τις περιοχές παθογονικότητας lvh και rtxA. Επομένως, η αξιολόγηση τόσο του ορότυπου όσο και των προαναφερθέντων παραγόντων παθογονικότητας είναι εξαιρετικά σημαντική προκειμένου να υπάρχει ολοκληρωμένη εκτίμηση κινδύνου ενός συστήματος νερού. Σκοπός της διατριβής: 1. Η ανάπτυξη μίας απλής, ταχείας, φθηνής και αξιόπιστης μεθοδολογίας για τον προσδιορισμό των οροτύπων στελεχών Lp, η οποία να μπορεί να εφαρμοστεί ως μέθοδος ρουτίνας σε ένα μικροβιολογικό εργαστήριο.2. Ο προσδιορισμός αξιόπιστων βιοδεικτών με σκοπό την ανίχνευση των περιοχών παθογονικότητας lvh και rtxA σε στελέχη τα οποία απομονώνονται κατά τη διάρκεια τακτικών ελέγχων. 3. Η επικύρωση των ανωτέρω μεθόδων. Υλικά και μέθοδοι: Για τη διατριβή χρησιμοποιήθηκαν 15 στελέχη αναφοράς και 150 περιβαλλοντικά στελέχη Lp (70 Lp1 και 80 Lp2-15 στελέχη). Οκτώ (8) Lp2-15 στελέχη οροτυπήθηκαν με τη χρήση μονοκλωνικών αντισωμάτων (monoclonal antibodies-Mab), ενώ τα υπόλοιπα περιβαλλοντικά στελέχη οροτυπήθηκαν με τη χρήση δοκιμασίας ανοσοσυγκόλησης. Σε όλα τα στελέχη πραγματοποιήθηκε PCR προς ανίχνευση των περιοχών lvh και rtxA. Κατόπιν, δημιουργήθηκαν ομάδες στελεχών αναφοράς και στελεχών επικύρωσης. Όλα τα στελέχη υποβλήθηκαν σε εξαγωγή των ριβοσωμικών και επιφανειακών πρωτεϊνών και ακολούθησε ανάλυση με MALDI-TOF MS. Στα πρωτογενή φάσματα των στελεχών των ομάδων αναφοράς έγινε επεξεργασία με το λογισμικό Mass-Up για την ανάδειξη βιοδεικτών τόσο για τον προσδιορισμό του οροτύπου όσο και για την ανίχνευση των περιοχών παθογονικότητας. Ακολούθησε επικύρωση της μεθόδου με τη χρήση των στελεχών των ομάδων επικύρωσης.Αποτελέσματα: Για τον προσδιορισμό του οροτύπου η ανάλυση με το λογισμικό Mass-up υπέδειξε πέντε (5) πρωτεϊνικές κορυφές ως πιθανούς βιοδείκτες για τον ορότυπο. Ο αλγόριθμος ταξινόμησε ορθά 115 από τα 132 στελέχη της ομάδας επικύρωσης με ακρίβεια 87,12% (95%CI:80,18-92,32%). Η ευαισθησία της μεθόδου προσδιορίστηκε στο 87,5% (95%CI:77.59-94.12%) και η ειδικότητα στο 86,67% (95%CI:75,41-94,06%). Σχετικά με την ανίχνευση των περιοχών παθογονικότητας προσδιορίστηκαν δύο πρωτεϊνικές κορυφές που μπορούν να χρησιμεύσουν ως βιοδείκτες για την rtxA περιοχή και μία για την lvh. Σε ό,τι αφορά την ανίχνευση της lvh περιοχής, με τη χρήση των βιοδεικτών, ταξινομήθηκαν ορθά τα 113 από τα 137 θετικά και όλα τα αρνητικά στελέχη (14 συνολικά). Η μέθοδος επέδειξε ευαισθησία 82,48% (95%CI:75,06-88,44%), ειδικότητα 100,00% (95%CI:76,84-100,00%) και ακρίβεια 84,11% (95%CI:77,28-89,54%). Ομοίως, για την rtxA περιοχή, 134 από τα 134 θετικά στελέχη και 14 από τα 17 αρνητικά στελέχη ταξινομήθηκαν ορθά. Η μέθοδος παρουσίασε ευαισθησία 100,00% (95%CI:97,28-100,00%), ειδικότητα 76,47% (95%CI:50,10-93,19%) και ακρίβεια 97,35% (95%CI:93,36-99,27%). Συμπεράσματα: Η μέθοδος MALDI-TOF MS, με τη χρήση του πρωτοκόλλου της πρωτεϊνικής εξαγωγής, αποδείχθηκε αξιόπιστη τόσο στον προσδιορισμό του οροτύπου της Lp όσο και στην ανίχνευση των περιοχών παθογονικότητας lvh και rtxA. Αυτοματοποίηση της μεθόδου και περαιτέρω αξιολόγηση με τη χρήση της τεχνικής της απευθείας επίστρωσης του μικροοργανισμού, ώστε να απλοποιηθεί ακόμη περισσότερο το πρωτόκολλο, θα μπορούσε να συνεισφέρει σε μεγαλύτερο βαθμό στην ταχεία, φθηνή και απλή αξιολόγηση κινδύνου, καθώς και στη διερεύνηση κρουσμάτων της Νόσου των Λεγεωναρίων.

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