scholarly journals Identification of Haemophilus influenzae Type b Isolates by Use of Matrix-Assisted Laser Desorption Ionization–Time of Flight Mass Spectrometry

2015 ◽  
Vol 53 (7) ◽  
pp. 2215-2224 ◽  
Author(s):  
Viktor Månsson ◽  
Fredrik Resman ◽  
Markus Kostrzewa ◽  
Bo Nilson ◽  
Kristian Riesbeck
Keyword(s):  
Mass Spectra ◽  
Laser Desorption Ionization ◽  
Type B ◽  
Ionization Time ◽  
Content Type ◽  
Maldi Tof Ms ◽  
Maldi Tof ◽  
Flight Mass Spectrometry ◽  
Maldi Biotyper ◽  
Tof Ms

Haemophilus influenzaetype b (Hib) is, in contrast to non-type bH. influenzae, associated with severe invasive disease, such as meningitis and epiglottitis, in small children. To date, accurateH. influenzaecapsule typing requires PCR, a time-consuming and cumbersome method. Matrix-assisted laser desorption ionization–time of flight mass spectrometry (MALDI-TOF MS) provides rapid bacterial diagnostics and is increasingly used in clinical microbiology laboratories. Here, MALDI-TOF MS was evaluated as a novel approach to separate Hib from otherH. influenzae. PCR-verified Hib and non-Hib reference isolates were selected based on genetic and spectral characteristics. Mass spectra of reference isolates were acquired and used to generate different classification algorithms for Hib/non-Hib differentiation using both ClinProTools and the MALDI Biotyper software. A test series of mass spectra from 33 Hib and 77 non-Hib isolates, all characterized by PCR, was used to evaluate the algorithms. Several algorithms yielded good results, but the two best were a ClinProTools model based on 22 separating peaks and subtyping main spectra (MSPs) using MALDI Biotyper. The ClinProTools model had a sensitivity of 100% and a specificity of 99%, and the results were 98% reproducible using a different MALDI-TOF MS instrument. The Biotyper subtyping MSPs had a sensitivity of 97%, a specificity of 100%, and 93% reproducibility. Our results suggest that it is possible to use MALDI-TOF MS to differentiate Hib from otherH. influenzae. This is a promising method for rapidly identifying Hib in unvaccinated populations and for the screening and surveillance of Hib carriage in vaccinated populations.

scholarly journals Rapid Identification of Clinically Relevant Members of the Genus Exophiala by Matrix-Assisted Laser Desorption Ionization–Time of Flight Mass Spectrometry and Description of Two Novel Species, Exophiala campbellii and Exophiala lavatrina

2017 ◽  
Vol 55 (4) ◽  
pp. 1162-1176 ◽  
Author(s):  
Andrew M. Borman ◽  
Mark Fraser ◽  
Adrien Szekely ◽  
Daniel E. Larcombe ◽  
Elizabeth M. Johnson
Keyword(s):  
Laser Desorption ◽  
Laser Desorption Ionization ◽  
Ionization Time ◽  
Content Type ◽  
Maldi Tof Ms ◽  
Maldi Tof ◽  
Flight Mass Spectrometry ◽  
Tof Ms ◽  
Matrix Assisted Laser ◽  
Matrix Assisted Laser Desorption

ABSTRACT Exophiala is a ubiquitous pleomorphic genus comprising at least 40 species, many of which have been associated with superficial, visceral, or systemic infections in humans, other mammals, or cold-blooded animals. In this study, we investigated the potential of matrix-assisted laser desorption–ionization time of flight mass spectrometry (MALDI-TOF MS) for the identification of Exophiala species. A total of 89 isolates (including 50 human and 4 animal clinical isolates) stored in the National Collection of Pathogenic Fungi were identified by PCR amplification and sequencing of internal transcribed spacer region 1. Eighty-three of the isolates corresponded to 16 known species within Exophiala/Rhinocladiella . The remaining six isolates are shown by phylogenetic analyses based on four loci to represent two novel Exophiala species. Four isolates from domestic bathrooms which form a sister species with Exophiala lecanii-corni are described here as Exophiala lavatrina sp. nov. The remaining two isolates, both from subcutaneous infections, are distantly related to Exophiala oligosperma and are described here as Exophiala campbellii sp. nov. The triazoles and terbinafine exhibited low MICs against all Exophiala isolates in vitro . MALDI-TOF MS successfully distinguished all 18 species and identified all isolates after appropriate reference spectra were created and added to commercial databases. Intraspecific mean log scores ranged from 1.786 to 2.584 and were consistently significantly higher than interspecific scores (1.193 to 1.624), with the exception of E. lecanii-corni and E. lavatrina , for which there was considerable log score overlap. In summary, MALDI-TOF MS allows the rapid and accurate identification of a wide range of clinically relevant Exophiala species.

scholarly journals Evaluation of matrix-assisted laser desorption ionization-time of flight mass spectrometry in diagnosis of clinical Nocardia species

2019 ◽  
Vol 43 (3) ◽  
pp. 157-162
Author(s):  
Gülşen Hasçelik ◽  
Markus Kostrzewa ◽  
Hamit Kaan Müştak ◽  
Celalettin Uner ◽  
Kadir Serdar Diker
Keyword(s):  
Species Level ◽  
Rrna Gene ◽  
Laser Desorption Ionization ◽  
Ionization Time ◽  
Maldi Tof Ms ◽  
Maldi Tof ◽  
Flight Mass Spectrometry ◽  
Maldi Biotyper ◽  
Rrna Gene Sequencing ◽  
Tof Ms

Abstract Background The routine identification to the species level of Nocardia genus by conventional methods is a fastidious and time-consuming process owing to the limited biochemical reactivity of these microorganisms, often requiring 1 or more days to complete identification. Matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS) is a new technology for definitive and rapid species identification. Methods We evaluated the MALDI-TOF MS for the identification of 44 clinical isolates of Nocardia species in comparison to 16S ribosomal RNA (rRNA) gene sequencing. Nocardia isolates were identified by microbiological examination, phenotypical tests and MALDI-TOF MS and the results were compared by 16S rRNA gene sequencing. Results Of the 44 Nocardia strains, the identification of 28 isolates was determined with MALDI Biotyper database. According to this, 16 isolates (57.1%) of the strain log scores were ≥2. Two (7.1%) were identified to the species level (log scores of ≥2) as Nocardia otitidiscaviarum. The addition of a newly established Nocardia database (16 new Nocardia strains included to the original database) did significantly improve the scores. The results were 43 (97.7%) correct identification to the species level (log scores of ≥2). Conclusions This study showed that the identification of clinical Nocardia isolates by the Bruker MALDI Biotyper is highly reliable, whereas identification rates are generally lower than those for some Gram-negative bacteria and Gram-positive cocci. Based on our data, the identification rates can be improved by validated new database entries and the results can be confirmed with nucleic acid sequence analysis.

scholarly journals Evaluation of Matrix-Assisted Laser Desorption Ionization−Time of Flight Mass Spectrometry for Identification of Mycobacterium species, Nocardia species, and Other Aerobic Actinomycetes

2015 ◽  
Vol 54 (2) ◽  
pp. 376-384 ◽  
Author(s):  
S. P. Buckwalter ◽  
S. L. Olson ◽  
B. J. Connelly ◽  
B. C. Lucas ◽  
A. A. Rodning ◽  
...  
Keyword(s):  
Laser Desorption ◽  
Laser Desorption Ionization ◽  
Ionization Time ◽  
Content Type ◽  
Maldi Tof Ms ◽  
Maldi Tof ◽  
Flight Mass Spectrometry ◽  
Aerobic Actinomycetes ◽  
Tof Ms ◽  
Matrix Assisted Laser

The value of matrix-assisted laser desorption ionization−time of flight mass spectrometry (MALDI-TOF MS) for the identification of bacteria and yeasts is well documented in the literature. Its utility for the identification of mycobacteria andNocardiaspp. has also been reported in a limited scope. In this work, we report the specificity of MALDI-TOF MS for the identification of 162Mycobacteriumspecies and subspecies, 53Nocardiaspecies, and 13 genera (totaling 43 species) of other aerobic actinomycetes using both the MALDI-TOF MS manufacturer's supplied database(s) and a custom database generated in our laboratory. The performance of a simplified processing and extraction procedure was also evaluated, and, similar to the results in an earlier literature report, our viability studies confirmed the ability of this process to inactivateMycobacterium tuberculosisprior to analysis. Following library construction and the specificity study, the performance of MALDI-TOF MS was directly compared with that of 16S rRNA gene sequencing for the evaluation of 297 mycobacteria isolates, 148Nocardiaspecies isolates, and 61 other aerobic actinomycetes isolates under routine clinical laboratory working conditions over a 6-month period. MALDI-TOF MS is a valuable tool for the identification of these groups of organisms. Limitations in the databases and in the ability of MALDI-TOF MS to rapidly identify slowly growing mycobacteria are discussed.

scholarly journals Novel Strategy for Rapidly and Safely Distinguishing Bacillus anthracis and Bacillus cereus by Use of Peptide Mass Fingerprints Based on Matrix-Assisted Laser Desorption Ionization–Time of Flight Mass Spectrometry

2020 ◽  
Vol 59 (1) ◽  
pp. e02358-20
Author(s):  
Jianchun Wei ◽  
Huijuan Zhang ◽  
Huifang Zhang ◽  
Enmin Zhang ◽  
Binghua Zhang ◽  
...  
Keyword(s):  
Bacillus Cereus ◽  
Bacillus Anthracis ◽  
Laser Desorption ◽  
Laser Desorption Ionization ◽  
Ionization Time ◽  
Content Type ◽  
Maldi Tof Ms ◽  
Maldi Tof ◽  
Flight Mass Spectrometry ◽  
Tof Ms

ABSTRACTThe objective of this study was to construct a rapid, high-throughput, and biosafety-compatible screening method for Bacillus anthracis and Bacillus cereus based on matrix-assisted laser desorption ionization–time of flight mass spectrometry (MALDI-TOF MS). MALDI-TOF MS coupled to ClinProTools was used to discover MALDI-TOF MS biomarker peaks and generate a classification model based on a genetic algorithm (GA) to differentiate between different Bacillus anthracis and Bacillus cereus isolates. Thirty Bacillus anthracis and 19 Bacillus cereus strains were used to construct and analyze the model, and 40 Bacillus strains were used for validation. For the GA screening model, the cross-validation values, which reflect the ability of the model to handle variability among the test spectra, and the recognition capability values, which reflect the model’s ability to correctly identify its component spectra, were all 100%. This model contained 10 biomarker peaks (m/z 3,339.9, 3,396.3, 3,682.4, 5,476.7, 6,610.6, 6,680.1, 7,365.3, 7,792.4, 9,475.8, and 10,934.1) used to correctly identify 28 Bacillus anthracis and 12 Bacillus cereus isolates from 40 Bacillus isolates, with a sensitivity and specificity of 100%. With the obvious advantages of being rapid, highly accurate, and highly sensitive and having a low cost and high throughput, MALDI-TOF MS ClinProTools is a powerful and reliable tool for screening Bacillus anthracis and Bacillus cereus strains.

scholarly journals Comparing Matrix-Assisted Laser Desorption Ionization–Time of Flight Mass Spectrometry and Phenotypic and Molecular Methods for Identification of Species within the Streptococcus anginosus Group

2015 ◽  
Vol 53 (11) ◽  
pp. 3580-3588 ◽  
Author(s):  
Raquel Arinto-Garcia ◽  
Marcos Daniel Pinho ◽  
João André Carriço ◽  
José Melo-Cristino ◽  
Mário Ramirez
Keyword(s):  
Laser Desorption Ionization ◽  
Ionization Time ◽  
Content Type ◽  
Maldi Tof Ms ◽  
Streptococcus Anginosus ◽  
Maldi Tof ◽  
Flight Mass Spectrometry ◽  
Subspecies Level ◽  
Human Infections ◽  
Tof Ms

The heterogeneity of members of theStreptococcus anginosusgroup (SAG) has traditionally hampered their correct identification. Recently, the group was subdivided into 6 taxa whose prevalence among human infections is poorly described. We evaluated the accuracy of the Rapid ID32 Strep test, matrix-assisted laser desorption ionization–time of flight mass spectrometry (MALDI-TOF MS), and a PCR multiplex method to identify 212 SAG isolates recovered from human infections to the species and subspecies level by using multilocus sequence analysis (MLSA) as the gold standard. We also determined the antimicrobial susceptibilities of the isolates. Representatives of all SAG taxa were found among our collection. MALDI-TOF MS and the Rapid ID32 Strep test correctly identified 92% and 68% of the isolates to the species level, respectively, but showed poor performance at the subspecies level, and the latter was responsible for major identification errors. The multiplex PCR method results were in complete agreement with the MLSA identifications but failed to distinguish the subspeciesStreptococcus constellatussubsp.pharyngisandS. constellatussubsp.viborgensis. A total of 145 MLSA sequence types were present in our collection, indicating that within each taxon a number of different lineages are capable of causing infection. Significant antibiotic resistance was observed only to tetracycline, erythromycin, and clindamycin and was present in most taxa. MALDI-TOF MS is a reliable method for routine SAG species identification, while the need for identification to the subspecies level is not clearly established.

scholarly journals Fusobacterium nucleatum Subspecies Identification by Matrix-Assisted Laser Desorption Ionization–Time of Flight Mass Spectrometry

2015 ◽  
Vol 53 (4) ◽  
pp. 1399-1402 ◽  
Author(s):  
Shuping Nie ◽  
Baoyu Tian ◽  
Xiaowei Wang ◽  
David H. Pincus ◽  
Martin Welker ◽  
...  
Keyword(s):  
Fusobacterium Nucleatum ◽  
Laser Desorption ◽  
Laser Desorption Ionization ◽  
Ionization Time ◽  
Content Type ◽  
Maldi Tof Ms ◽  
Maldi Tof ◽  
Flight Mass Spectrometry ◽  
Tof Ms ◽  
Matrix Assisted Laser

We explored the use of matrix-assisted laser desorption ionization–time of flight mass spectrometry (MALDI-TOF MS) for identification ofFusobacterium nucleatumsubspecies. MALDI-TOF MS spectra of fiveF. nucleatumsubspecies (animalis,fusiforme,nucleatum,polymorphum, andvincentii) were analyzed and divided into four distinct clusters, including subsp.animalis,nucleatum,polymorphum, andfusiforme/vincentii. MALDI-TOF MS with the modified SARAMIS database further correctly identified 28 of 34F. nucleatumclinical isolates to the subspecies level.

scholarly journals Use of Matrix-Assisted Laser Desorption Ionization–Time of Flight Mass Spectrometry for Identification of Molds of the Fusarium Genus

2014 ◽  
Vol 53 (2) ◽  
pp. 465-476 ◽  
Author(s):  
David Triest ◽  
Dirk Stubbe ◽  
Koen De Cremer ◽  
Denis Piérard ◽  
Anne-Cécile Normand ◽  
...  
Keyword(s):  
Species Complex ◽  
Laser Desorption ◽  
Laser Desorption Ionization ◽  
Ionization Time ◽  
Content Type ◽  
Maldi Tof Ms ◽  
Maldi Tof ◽  
Flight Mass Spectrometry ◽  
Species Complexes ◽  
Tof Ms

The rates of infection withFusariummolds are increasing, and a diverse number ofFusariumspp. belonging to different species complexes can cause infection. Conventional species identification in the clinical laboratory is time-consuming and prone to errors. We therefore evaluated whether matrix-assisted laser desorption ionization–time of flight mass spectrometry (MALDI-TOF MS) is a useful alternative. The 289Fusariumstrains from the Belgian Coordinated Collections of Microorganisms (BCCM)/Institute of Hygiene and Epidemiology Mycology (IHEM) culture collection with validated sequence-based identities and comprising 40 species were used in this study. An identification strategy was developed, applying a standardized MALDI-TOF MS assay and an in-house reference spectrum database.In vitroantifungal testing was performed to assess important differences in susceptibility between clinically relevant species/species complexes. We observed that no incorrect species complex identifications were made by MALDI-TOF MS, and 82.8% of the identifications were correct to the species level. This success rate was increased to 91% by lowering the cutoff for identification. Although the identification of the correct species complex member was not always guaranteed, antifungal susceptibility testing showed that discriminating betweenFusariumspecies complexes can be important for treatment but is not necessarily required between members of a species complex. With this perspective, someFusariumspecies complexes with closely related members can be considered as a whole, increasing the success rate of correct identifications to 97%. The application of our user-friendly MALDI-TOF MS identification approach resulted in a dramatic improvement in both time and accuracy compared to identification with the conventional method. A proof of principle of our MALDI-TOF MS approach in the clinical setting using recently isolatedFusariumstrains demonstrated its validity.

Leptospira ainlahdjerensis sp. nov., Leptospira ainazelensis sp. nov., Leptospira abararensis sp. nov. and Leptospira chreensis sp. nov., four new species isolated from water sources in Algeria

2021 ◽  
Vol 71 (12) ◽  
Author(s):  
Anissa Amara Korba ◽  
Hakim Lounici ◽  
Malia Kainiu ◽  
Antony T. Vincent ◽  
Jean-François Mariet ◽  
...  
Keyword(s):  
Novel Species ◽  
Laser Desorption ◽  
Laser Desorption Ionization ◽  
Ionization Time ◽  
Content Type ◽  
Maldi Tof Ms ◽  
Link Type ◽  
Maldi Tof ◽  
Flight Mass Spectrometry ◽  
Tof Ms

Leptospira strains were isolated from freshwater sampled at four sites in Algeria and characterized by whole-genome sequencing and matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS). The cells were spiral-shaped and motile. Phylogenetic and MALDI-TOF MS analyses showed that the strains can be clearly distinguished from the other described species in the genus Leptospir a, therefore representing two novel species of the pathogen subclade P1 and two novel species of the saprophyte subclade S1. The names Leptospira ainlahdjerensis sp. nov. (type strain 201903070T=KIT0297T=CIP111912T), Leptospira ainazelensis sp. nov. (201903071T=KIT0298T=CIP111913T), Leptospira abararensis sp. nov. (201903074T=KIT0299T=CIP111914T) and Leptospira chreensis (201903075T=KIT0300T=CIP111915T) are proposed.

scholarly journals Implementation of Matrix-Assisted Laser Desorption Ionization–Time of Flight Mass Spectrometry in Routine Clinical Laboratories Improves Identification of Coagulase-Negative Staphylococci and Reveals the Pathogenic Role of Staphylococcus lugdunensis

2015 ◽  
Vol 53 (7) ◽  
pp. 2030-2036 ◽  
Author(s):  
Xavier Argemi ◽  
Philippe Riegel ◽  
Thierry Lavigne ◽  
Nicolas Lefebvre ◽  
Nicolas Grandpré ◽  
...  
Keyword(s):  
Laser Desorption Ionization ◽  
Coagulase Negative Staphylococci ◽  
Ionization Time ◽  
Content Type ◽  
Maldi Tof Ms ◽  
Maldi Tof ◽  
Flight Mass Spectrometry ◽  
Phenotypic Methods ◽  
Tof Ms

The use of matrix-assisted laser desorption ionization–time of flight mass spectrometry (MALDI-TOF MS) for staphylococcal identification is now considered routine in laboratories compared with the conventional phenotypical methods previously used. We verified its microbiological relevance for identifying the main species of coagulase-negative staphylococci (CoNS) by randomly selecting 50 isolates. From 1 January 2007 to 31 August 2008, 12,479 staphylococci were isolated with phenotypic methods, of which 4,594 were identified asStaphylococcus aureusand 7,885 were coagulase negative staphylococci. Using MALDI-TOF MS from 1 January 2011 to 31 August 2012, 14,913 staphylococci were identified, with 5,066 asS. aureusand 9,847 as CoNS. MALDI-TOF MS allowed the identification of approximately 85% of the CoNS strains, whereas only 14% of the CoNS strains were identified to the species level with phenotypic methods because they were often considered contaminants. Furthermore, the use of MALDI-TOF MS revealed the occurrence of recently characterizedStaphylococcusspecies, such asS. pettenkoferi,S. condimenti, andS. piscifermentans. Microbiological relevance analysis further revealed that some species displayed a high rate of microbiological significance, i.e., 40% of theS. lugdunensisstrains included in the analysis were associated with infection risk. This retrospective microbiological study confirms the role of MALDI-TOF MS in clinical settings for the identification of staphylococci with clinical consequences. The species distribution reveals the occurrence of the recently identified speciesS. pettenkoferiand putative virulent species, includingS. lugdunensis.

scholarly journals Antifungal Susceptibility Testing of Aspergillus spp. by Using a Composite Correlation Index (CCI)-Based Matrix-Assisted Laser Desorption Ionization–Time of Flight Mass Spectrometry Method Appears To Not Offer Benefit over Traditional Broth Microdilution Testing

2017 ◽  
Vol 55 (7) ◽  
pp. 2030-2034 ◽  
Author(s):  
Melissa R. Gitman ◽  
Lisa McTaggart ◽  
Joanna Spinato ◽  
Rahgavi Poopalarajah ◽  
Erin Lister ◽  
...  
Keyword(s):  
Susceptibility Testing ◽  
Antifungal Susceptibility ◽  
Laser Desorption Ionization ◽  
Wild Type ◽  
Ionization Time ◽  
Content Type ◽  
Maldi Tof Ms ◽  
Maldi Tof ◽  
Flight Mass Spectrometry ◽  
Tof Ms

ABSTRACT Aspergillus spp. cause serious invasive lung infections, and Aspergillus fumigatus is the most commonly encountered clinically significant species. Voriconazole is considered to be the drug of choice for treating A. fumigatus infections; however, rising resistance rates have been reported. We evaluated a matrix-assisted laser desorption ionization–time of flight mass spectrometry (MALDI-TOF MS)-based method for the differentiation between wild-type and non-wild-type isolates of 20 Aspergillus spp. (including 2 isolates of Aspergillus ustus and 1 of Aspergillus calidoustus that were used as controls due their intrinsic low azole susceptibility with respect to the in vitro response to voriconazole). At 30 and 48 h of incubation, there was complete agreement between Cyp51A sequence analysis, broth microdilution, and MALDI-TOF MS classification of isolates as wild type or non-wild type. In this proof-of-concept study, we demonstrated that MALDI-TOF MS can be used to accurately detect A. fumigatus strains with reduced voriconazole susceptibility. However, rather than proving to be a rapid and simple method for antifungal susceptibility testing, this particular MS-based method showed no benefit over conventional testing methods.

Sign in / Sign up

Export Citation Format

Share Document