Applications of MALDI-TOF MS in environmental microbiology

The Analyst ◽  
2016 ◽  
Vol 141 (10) ◽  
pp. 2827-2837 ◽  
Author(s):  
Inês C. Santos ◽  
Zacariah L. Hildenbrand ◽  
Kevin A. Schug
Keyword(s):  
Laser Desorption ◽  
Laser Desorption Ionization ◽  
Ionization Time ◽  
Microbial Identification ◽  
Desorption Ionization ◽  
Maldi Tof ◽  
P Matrix ◽  
Tof Ms ◽  
Matrix Assisted Laser ◽  
Matrix Assisted Laser Desorption

Matrix-assisted laser desorption ionization time-of-flight (MALDI-TOF) mass spectrometry (MS) is an emerging technique for microbial identification, characterization, and typing.

scholarly journals Assessment of Reproducibility of Matrix-Assisted Laser Desorption Ionization–Time of Flight Mass Spectrometry for Bacterial and Yeast Identification

2015 ◽  
Vol 53 (7) ◽  
pp. 2349-2352 ◽  
Author(s):  
Lars F. Westblade ◽  
Omai B. Garner ◽  
Karen MacDonald ◽  
Constance Bradford ◽  
David H. Pincus ◽  
...  
Keyword(s):  
Laser Desorption ◽  
Laser Desorption Ionization ◽  
Ionization Time ◽  
Maldi Tof Ms ◽  
Microbial Identification ◽  
Desorption Ionization ◽  
Maldi Tof ◽  
Tof Ms ◽  
Matrix Assisted Laser ◽  
Matrix Assisted Laser Desorption

Matrix-assisted laser desorption ionization–time of flight (MALDI-TOF) mass spectrometry (MS) has revolutionized the identification of clinical bacterial and yeast isolates. However, data describing the reproducibility of MALDI-TOF MS for microbial identification are scarce. In this study, we show that MALDI-TOF MS-based microbial identification is highly reproducible and can tolerate numerous variables, including differences in testing environments, instruments, operators, reagent lots, and sample positioning patterns. Finally, we reveal that samples of bacterial and yeast isolates prepared for MALDI-TOF MS identification can be repeatedly analyzed without compromising organism identification.

The Identification of Microbial Pathogens Using Matrix Assisted Laser Desorption Ionization Time of Flight in Medical Intensive Care Unit Beni-Suef University Hospital

2021 ◽  
Vol 30 (3) ◽  
pp. 65-69
Author(s):  
Marwa N. Mohamed ◽  
Ahmed F. Azmy ◽  
Ehab M. Fahmy ◽  
Mervat G. Elanany ◽  
Nesreen M. Kamel
Keyword(s):  
Time Of Flight ◽  
Laser Desorption ◽  
Laser Desorption Ionization ◽  
Ionization Time ◽  
Microbial Identification ◽  
Desorption Ionization ◽  
Maldi Tof ◽  
Kappa Agreement ◽  
Matrix Assisted Laser ◽  
Matrix Assisted Laser Desorption

Background: Matrix Assisted Laser Desorption Ionization Time of Flight (MALDI-TOF) is a novel technique for identification of microbes. This new method led to a new era in microbial identification because of its rapid, accurate, valid, simple and relatively decreased cost. Objectives: The aim of this study was identification of predominant pathogens by MALDI-TOF technique. Methodology: Pathogens were identified by both conventional methods and MALDI-TOF. Results: From July till December 2018, predominant pathogens were Klebsiella pneumoniae (21%), Pseudomonas aeroguinosa and Candida each constitutes (17%), E-coli (10%), Staph. aureus (9%), Acinetobacter (9%). Identification of isolates (from September to December 2018) by MALDI-TOF revealed a total agreement of (94.1%) with conventional method at genus level, (88.2%) at level of species. Kappa agreement revealed almost perfect correlation between both techniques. Conclusion: The MALDI-TOF results might suggest that its’ usage may be dependable for microbiological identification.

scholarly journals Matrix-Assisted Laser Desorption Ionization–Time of Flight (MALDI-TOF) Mass Spectrometry for Detection of Antibiotic Resistance Mechanisms: from Research to Routine Diagnosis

2013 ◽  
Vol 26 (1) ◽  
pp. 103-114 ◽  
Author(s):  
Jaroslav Hrabák ◽  
Eva Chudáčková ◽  
Radka Walková
Keyword(s):  
Antibiotic Resistance ◽  
Laser Desorption ◽  
Laser Desorption Ionization ◽  
Ionization Time ◽  
Maldi Tof Ms ◽  
Desorption Ionization ◽  
Maldi Tof ◽  
Tof Ms ◽  
Matrix Assisted Laser ◽  
Matrix Assisted Laser Desorption

SUMMARYMatrix-assisted laser desorption ionization–time of flight mass spectrometry (MALDI-TOF MS) has been successfully applied as an identification procedure in clinical microbiology and has been widely used in routine laboratory practice because of its economical and diagnostic benefits. The range of applications of MALDI-TOF MS has been growing constantly, from rapid species identification to labor-intensive proteomic studies of bacterial physiology. The purpose of this review is to summarize the contribution of the studies already performed with MALDI-TOF MS concerning antibiotic resistance and to analyze future perspectives in this field. We believe that current research should continue in four main directions, including the detection of antibiotic modifications by degrading enzymes, the detection of resistance mechanism determinants through proteomic studies of multiresistant bacteria, and the analysis of modifications of target sites, such as ribosomal methylation. The quantification of antibiotics is suggested as a new approach to study influx and efflux in bacterial cells. The results of the presented studies demonstrate that MALDI-TOF MS is a relevant tool for the detection of antibiotic resistance and opens new avenues for both clinical and experimental microbiology.

scholarly journals Differentiation of Brachyspira spp. isolated from laying hens using PCR-based methods and matrix-assisted laser desorption/ionization time-of-flight mass spectrometry

2018 ◽  
Vol 30 (4) ◽  
pp. 545-553
Author(s):  
Monika Harms ◽  
Volker Schmidt ◽  
Tilo Heydel ◽  
Jutta Hauptmann ◽  
Christine Ahlers ◽  
...  
Keyword(s):  
Laser Desorption ◽  
Laser Desorption Ionization ◽  
Ionization Time ◽  
Maldi Tof Ms ◽  
Desorption Ionization ◽  
Maldi Tof ◽  
Flight Mass Spectrometry ◽  
Tof Ms ◽  
Matrix Assisted Laser ◽  
Matrix Assisted Laser Desorption

Avian intestinal spirochetosis (AIS), an important but neglected disease in laying hens, is caused by Brachyspira pilosicoli, B. intermedia, and B. alvinipulli. Poultry are also frequently colonized by putatively nonpathogenic species such as B. murdochii and B. innocens. We evaluated the differentiation of Brachyspira species by 3 methods: sequencing of the reduced nicotinamide adenine dinucleotide (NADH) oxidase gene ( nox), matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS), and a new multiplex (m)PCR targeting genes such as the tryptophanase A gene ( tnaA) and the p-aminobenzoyl-glutamate hydrolase subunit B gene ( abgB). Sequencing of 414 bp of the nox PCR amplification products generated from 41 pure cultures of avian Brachyspira isolates allowed presumptive species identification in 33 isolates with at least 99% identity in basic local alignment search tool analysis, including B. pilosicoli, B. intermedia, B. murdochii, B. innocens, and “ B. pulli”. MALDI-TOF MS analysis was found to be a reliable tool for differentiation after extension of the manufacturer’s database. In the mPCR, all isolates identified as B. pilosicoli and B. intermedia were positive for abgB and tnaA, respectively. The mPCR might be very useful in detecting Brachyspira species in mixed cultures including not only nonpathogenic species, such as B. innocens, but also one of the AIS pathogens. We found that MALDI-TOF MS analysis combined with the mPCR targeting tnaA and abgB was suitable for the identification of avian isolates of B. pilosicoli and B. intermedia, 2 important agents of AIS.

scholarly journals Identification of clinical dermatophyte isolates obtained from Iran by matrix-assisted laser desorption/ionization time-offlight mass spectrometry

2019 ◽  
Author(s):  
Mohammad Taghi Hedayati ◽  
Saham Ansari ◽  
Bahram Ahmadi ◽  
Mojtaba Taghizadeh Armaki ◽  
Tahereh Shokohi ◽  
...  
Keyword(s):  
Laser Desorption ◽  
Laser Desorption Ionization ◽  
Ionization Time ◽  
Maldi Tof Ms ◽  
Desorption Ionization ◽  
Maldi Tof ◽  
Protein Spectra ◽  
Tof Ms ◽  
Matrix Assisted Laser ◽  
Matrix Assisted Laser Desorption

Background and Purpose: Matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) is widely used to discriminate among pathogenic microorganisms in clinical laboratories. The aim of this study was to assess the utility of MALDI-TOF MS in the routine identification of clinical dermatophyte isolates obtained from various geographical regions of Iran. Materials and Methods: A total of 94 isolates, including Trichophyton interdigitale (n=44), T. rubrum (n=40), T. tonsurans (n=4), Microsporum canis (n=4), and Epidermophyton floccosum (n=1), were analyzed in this study. The identity of each isolate was determined by polymerase chani reaction amplification and sequencing of the internal transcribed spacer (ITS) region of nuclear-encoded ribosomal DNA and also MALDI-TOF MS. The obtained data by molecular approach were compared with MALDI-TOF MS. Results: The MALDI-TOF MS led to the identification of 44 (47%) isolates at the species level by generating the spectral score values of ≥ 2.0. However, there was not sufficient agreement between the results of the molecular-based ITS identification methods and MALDI-TOF MS in the species identification of 16 (17%) isolates. The Bruker Daltonics database was also not able to identify protein spectra related to 12 isolates (13%), including T. interdigitale (n=5), T. rubrum (n=4), M. canis (n=2), and T. tonsurans (n=1). Conclusion: According to the results, the utility of MALDI-TOF MS as a routine diagnostic tool for the accurate and reliable identification of dermatophytes can be justified whenever the protein spectra of a large set of worldwide clinical isolates are included in the commercial libraries. In addition, MALDI-TOF MS can be alternatively used to construct an in-house reference database.

scholarly journals Proteomic changes in bacteria caused by exposure to environmental conditions can be detected by Matrix-Assisted Laser Desorption/Ionization – Time of Flight (MALDI-ToF) Mass Spectrometry

2020 ◽  
Author(s):  
Denise Chac ◽  
Melissa Kordahi ◽  
Leandra Brettner ◽  
Arushi Verma ◽  
Paul McCleary ◽  
...  
Keyword(s):  
Laser Desorption ◽  
Laser Desorption Ionization ◽  
Ionization Time ◽  
Maldi Tof Ms ◽  
Phenotypic Differences ◽  
Desorption Ionization ◽  
Maldi Tof ◽  
Tof Ms ◽  
Matrix Assisted Laser ◽  
Matrix Assisted Laser Desorption

ABSTRACTIn the past decade, matrix-assisted laser desorption/ionization time-of-flight (MALDI-ToF) mass spectrometry (MS) has become a timely and cost-effective alternative to bacterial identification. The MALDI-ToF MS technique analyzes the total protein of culturable microorganisms at the species level and produces a mass spectra based on peptides which is compared to a database of identified profiles. Consequently, unique signatures of each microorganism are produced allowing identification at the species and, more importantly, strain level. Our present study proposes that the MALDI-ToF MS can be further used to screen functional and metabolic differences. While other studies applied the MALDI-ToF technique to identify subgroups within species, we investigated how various environmental factors could alter the unique bacterial signatures. We found that genetic and phenotypic differences between microorganisms belonging to the same species can be reflected in peptide-mass fingerprints generated by MALDI-ToF MS. These results suggest that MALDI-ToF MS can screen intra-species phenotypic differences of several microorganisms.

scholarly journals Microbial Typing by Matrix-Assisted Laser Desorption Ionization–Time of Flight Mass Spectrometry: Do We Need Guidance for Data Interpretation?

2014 ◽  
Vol 53 (3) ◽  
pp. 760-765 ◽  
Author(s):  
Sébastien Spinali ◽  
Alex van Belkum ◽  
Richard V. Goering ◽  
Victoria Girard ◽  
Martin Welker ◽  
...  
Keyword(s):  
Laser Desorption ◽  
Laser Desorption Ionization ◽  
Ionization Time ◽  
Maldi Tof Ms ◽  
Desorption Ionization ◽  
Maldi Tof ◽  
Flight Mass Spectrometry ◽  
Tof Ms ◽  
Matrix Assisted Laser ◽  
Matrix Assisted Laser Desorption

The integration of matrix-assisted laser desorption ionization–time of flight mass spectrometry (MALDI-TOF MS) in clinical microbiology has revolutionized species identification of bacteria, yeasts, and molds. However, beyond straightforward identification, the method has also been suggested to have the potential for subspecies-level or even type-level epidemiological analyses. This minireview explores MALDI-TOF MS-based typing, which has already been performed on many clinically relevant species. We discuss the limits of the method's resolution and we suggest interpretative criteria allowing valid comparison of strain-specific data. We conclude that guidelines for MALDI-TOF MS-based typing can be developed along the same lines as those used for the interpretation of data from pulsed-field gel electrophoresis (PFGE).

scholarly journals Discrimination of biofilm-producing Stenotrophomonas maltophilia clinical strains by matrix-assisted laser desorption ionization–time of flight

PLoS ONE ◽  
2020 ◽  
Vol 15 (12) ◽  
pp. e0244751
Author(s):  
Edeer Montoya-Hinojosa ◽  
Paola Bocanegra-Ibarias ◽  
Elvira Garza-González ◽  
Óscar Manuel Alonso-Ambriz ◽  
Gabriela Aimee Salazar-Mata ◽  
...  
Keyword(s):  
Stenotrophomonas Maltophilia ◽  
Laser Desorption ◽  
Laser Desorption Ionization ◽  
Ionization Time ◽  
Desorption Ionization ◽  
Maldi Tof ◽  
Biofilm Production ◽  
Tof Ms ◽  
Matrix Assisted Laser ◽  
Matrix Assisted Laser Desorption

Stenotrophomonas maltophilia is a Gram-negative drug-resistant pathogen responsible for healthcare-associated infections. The aim was to search for biomarker peaks that could rapidly detect biofilm production in S. maltophilia clinical isolates obtained from two tertiary care hospitals in Mexico. Isolates were screened for the presence of biofilm-associated genes, in which the fsnR gene was associated with biofilm production (p = 0.047), whereas the rmlA+ genotype was associated with the rpfF- genotype (p = 0.017). Matrix-assisted laser desorption ionization–time of flight (MALDI-TOF) mass spectra comparison yielded three potential biomarker peaks (4661, 6074, and 6102 m/z) of biofilm-producing rmlA+ and rpfF- genotypes with >90% sensitivity (p<0.001). MALDI-TOF MS analyses showed a correlation between the relative abundance of 50S ribosomal proteins (L30 and L33) and the presence of the fnsR, rmlA and rpfF-2 genes, suggested to play a role in biofilm formation. Isolates obtained in the intensive care unit showed low clonality, suggesting no transmission within the hospital ward. The detection of biomarkers peaks by MALDI-TOF MS could potentially be used to early recognize and discriminate biofilm-producing S. maltophilia strains and aid in establishing appropriate antibiotic therapy.

scholarly journals Identification of Adult Fasciola spp. Using Matrix-Assisted Laser/Desorption Ionization Time-of-Flight (MALDI-TOF) Mass Spectrometry

2020 ◽  
Vol 9 (1) ◽  
pp. 82
Author(s):  
Issa Sy ◽  
Lena Margardt ◽  
Emmanuel O. Ngbede ◽  
Mohammed I. Adah ◽  
Saheed T. Yusuf ◽  
...  
Keyword(s):  
Laser Desorption ◽  
Laser Desorption Ionization ◽  
Ionization Time ◽  
Specific Identification ◽  
Maldi Tof Ms ◽  
Maldi Tof ◽  
Species Specific ◽  
Tof Ms ◽  
Matrix Assisted Laser ◽  
Matrix Assisted Laser Desorption

Fascioliasis is a neglected trematode infection caused by Fasciola gigantica and Fasciola hepatica. Routine diagnosis of fascioliasis relies on macroscopic identification of adult worms in liver tissue of slaughtered animals, and microscopic detection of eggs in fecal samples of animals and humans. However, the diagnostic accuracy of morphological techniques and stool microscopy is low. Molecular diagnostics (e.g., polymerase chain reaction (PCR)) are more reliable, but these techniques are not routinely available in clinical microbiology laboratories. Matrix-assisted laser/desorption ionization time-of-flight (MALDI-TOF) mass spectrometry (MS) is a widely-used technique for identification of bacteria and fungi; yet, standardized protocols and databases for parasite detection need to be developed. The purpose of this study was to develop and validate an in-house database for Fasciola species-specific identification. To achieve this goal, the posterior parts of seven adult F. gigantica and one adult F. hepatica were processed and subjected to MALDI-TOF MS to create main spectra profiles (MSPs). Repeatability and reproducibility tests were performed to develop the database. A principal component analysis revealed significant differences between the spectra of F. gigantica and F. hepatica. Subsequently, 78 Fasciola samples were analyzed by MALDI-TOF MS using the previously developed database, out of which 98.7% (n = 74) and 100% (n = 3) were correctly identified as F. gigantica and F. hepatica, respectively. Log score values ranged between 1.73 and 2.23, thus indicating a reliable identification. We conclude that MALDI-TOF MS can provide species-specific identification of medically relevant liver flukes.

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