scholarly journals STUDY OF THE MASS-SPECTORS’ FEATURES OF SPORES AND VEGETATIVE FORMS OF BACILLUS ANTHRACIS BY THE METHOD OF TIME OF FLIGHT MASS-SPECTROMETRY

2018 ◽  
pp. 66-72
Author(s):  
D. V. Ulshina ◽  
E. I. Eremenko ◽  
D. A. Kovalev ◽  
A. G. Ryazanova ◽  
I. V. Kuznetsova ◽  
...  
Keyword(s):  
Bacillus Anthracis ◽  
Causative Agent ◽  
Protein Profiling ◽  
Protein Profiles ◽  
Maldi Tof Ms ◽  
Maldi Tof ◽  
Flight Mass Spectrometry ◽  
Vegetative Form ◽  
Maldi Tof Mass Spectra ◽  
Tof Ms

Aim. Investigation of the features of the protein profiles of the spore and vegetative form of the anthrax microbe by the MALDI-TOF MS method using the resources of the Mass-Up program and the package for the statistical software with open source code R. Materials and methods. Spores and vegetative forms of 32 strains of B. anthracis from the collection of microorganisms of the Stavropol Research Institute for Plague Control, including 8 strains isolated from an outbreak of anthrax in Yamal in 2016. Protein profiling was carried out on the Microflex MALDI-TOF mass spectrometer «Bruker Daltonics». Results. The alternative bioinformational-statistical approach used to analyze the MALDI-TOF mass spectra of the causative agent of anthrax made it possible to differentiate the spores and vegetative forms of the microbe based on the identification of the corresponding groups of biomarkers. Conclusion. A comparison of vegetative and spore cells of typical and atypical strains of anthrax causative agent on the basis of MALDI-TOF MS data was made. It has been experimentally confirmed that the protein profiles of cultures of Bacillus anthracis of the spore and vegetative form differ significantly, and this difference can be used to search for potential markers of each of the forms.

scholarly journals APPLICATION OF TIME-OF-FLIGHT MASS-SPECTROMETRY FOR DETECTION OF CAUSATIVE AGENT OF BRUCELLOSIS IN BLOOD SAMPLES IN EXPERIMENT

2017 ◽  
pp. 9-17
Author(s):  
D. V. Ulshina ◽  
D. A. Kovalev ◽  
D. G. Ponomarenko ◽  
D. V. Rusanova ◽  
N. M. Shvetsova ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
Causative Agent ◽  
Brucella Melitensis ◽  
Time Of Flight ◽  
Protein Profiling ◽  
Blood Samples ◽  
Maldi Tof Ms ◽  
Maldi Tof ◽  
Flight Mass Spectrometry ◽  
Tof Ms

Aim.Study the possibility to apply time-of-flight mass-spectrometry for detection of causative agent of brucellosis in blood. Materials and methods. Brucella strains: 5 Brucella melitensis and 21 Brucella abortus. Protein profiling in linear mode on MALD1-TOF mass-spectrometer Microflex «Bruker Daltonics». Results. Technique for disinfection and preparation of blood samples was modified and optimized for MALDI-TOF MS analysis. 120 representative protein profiles of sera extract were obtained that contain brucellosis causative agent. A resulting peak-list (super-spectrum) of the studied protein fraction of blood extract of a conditionally healthy human within the studied group was formed and analyzed. Conclusion. A scheme of brucella detection in blood samples by MALDI-TOF MS is proposed, based on detection of a complex of 15 genus-specific fragments. Signals on mass-spectra of extracts of leukocyte fraction of blood, artificially contaminated with brucellosis causative agents are characterized.

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.

Accurate identification of Australian mosquitoes using protein profiling

Parasitology ◽  
2018 ◽  
Vol 146 (4) ◽  
pp. 462-471 ◽  
Author(s):  
Andrea L. Lawrence ◽  
Jana Batovska ◽  
Cameron E. Webb ◽  
Stacey E. Lynch ◽  
Mark J. Blacket ◽  
...  
Keyword(s):  
Dna Barcoding ◽  
Disease Risk ◽  
Genetic Relationships ◽  
Mosquito Species ◽  
Protein Profiling ◽  
Accurate Identification ◽  
Maldi Tof Ms ◽  
Maldi Tof ◽  
Flight Mass Spectrometry ◽  
Tof Ms

AbstractAustralian mosquito species significantly impact human health through nuisance biting and the transmission of endemic and exotic pathogens. Surveillance programmes designed to provide an early warning of mosquito-borne disease risk require reliable identification of mosquitoes. This study aimed to investigate the viability of Matrix-Assisted Laser Desorption/Ionization–Time-of-Flight Mass Spectrometry (MALDI-TOF MS) as a rapid and inexpensive approach to the identification of Australian mosquitoes and was validated using a three-step taxonomic approach. A total of 300 mosquitoes representing 21 species were collected from south-eastern New South Wales and morphologically identified. The legs from the mosquitoes were removed and subjected to MALDI-TOF MS analysis. Fifty-eight mosquitoes were sequenced at the cytochrome c oxidase subunit I (cox1) gene region and genetic relationships were analysed. We create the first MALDI-TOF MS spectra database of Australian mosquito species including 19 species. We clearly demonstrate the accuracy of MALDI-TOF MS for identification of Australian mosquitoes. It is especially useful for assessing gaps in the effectiveness of DNA barcoding by differentiating closely related taxa. Indeed, cox1 DNA barcoding was not able to differentiate members of the Culex pipiens group, Cx. quinquefasciatus and Cx. pipiens molestus, but these specimens were correctly identified using MALDI-TOF MS.

scholarly journals Identification of the ‘Streptococcus anginosus group’ by matrix-assisted laser desorption ionization – time-of-flight mass spectrometry

2014 ◽  
Vol 63 (9) ◽  
pp. 1143-1147 ◽  
Author(s):  
Katherine Woods ◽  
David Beighton ◽  
John L. Klein
Keyword(s):  
Species Level ◽  
Direct Transfer ◽  
Laser Desorption Ionization ◽  
Ionization Time ◽  
Maldi Tof Ms ◽  
Streptococcus Anginosus ◽  
Maldi Tof ◽  
Flight Mass Spectrometry ◽  
Transfer Method ◽  
Tof Ms

Matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) provides rapid, accurate and cost-effective identification of a range of bacteria and is rapidly changing the face of routine diagnostic microbiology. However, certain groups of bacteria, for example streptococci (in particular viridans or non-haemolytic streptococci), are less reliably identified by this method. We studied the performance of MALDI-TOF MS for identification of the ‘Streptococcus anginosus group’ (SAG) to species level. In total, 116 stored bacteraemia isolates identified by conventional methods as belonging to the SAG were analysed by MALDI-TOF MS. Partial 16S rRNA gene sequencing, supplemented with sialidase activity testing, was performed on all isolates to provide ‘gold standard’ identification against which to compare MALDI-TOF MS performance. Overall, 100 % of isolates were correctly identified to the genus level and 93.1 % to the species level by MALDI-TOF MS. However, only 77.6 % were correctly identified to the genus level and 59.5 % to the species level by a MALDI-TOF MS direct transfer method alone. Use of a rapid in situ extraction method significantly improved identification rates when compared with the direct transfer method (P<0.001). We recommend routine use of this method to reduce the number of time-consuming full extractions required for identification of this group of bacteria by MALDI-TOF MS in the routine diagnostic laboratory. Only 22 % (1/9) of Streptococcus intermedius isolates were reliably identified by MALDI-TOF MS to the species level, even after full extraction. MALDI-TOF MS reliably identifies S. anginosus and Streptococcus constellatus to the species level but does not reliably identify S. intermedius.

Identification of Lice Stored in Alcohol Using MALDI-TOF MS

2020 ◽  
Author(s):  
Hanene Benyahia ◽  
Basma Ouarti ◽  
Adama Zan Diarra ◽  
Mehdi Boucheikhchoukh ◽  
Mohamed Nadir Meguini ◽  
...  
Keyword(s):  
Economic Consequences ◽  
Correct Identification ◽  
Protein Profiles ◽  
Innovative Strategy ◽  
Maldi Tof Ms ◽  
Pediculus Humanus ◽  
Maldi Tof ◽  
Ms Analysis ◽  
Storage Methods ◽  
Tof Ms

Abstract Lice pose major public and veterinary health problems with economic consequences. Their identification is essential and requires the development of an innovative strategy. MALDI-TOF MS has recently been proposed as a quick, inexpensive, and accurate tool for the identification of arthropods. Alcohol is one of the most frequently used storage methods and makes it possible to store samples for long periods at room temperature. Several recent studies have reported that alcohol alters protein profiles resulting from MS analysis. After preliminary studies on frozen lice, the purpose of this research was to evaluate the influence of alcohol preservation on the accuracy of lice identification by MALDI-TOF MS. To this end, lice stored in alcohol for variable periods were submitted for MS analysis and sample preparation protocols were optimized. The reproducibility and specificity of the MS spectra obtained on both these arthropod families allowed us to implement the reference MS spectra database (DB) with protein profiles of seven lice species stored in alcohol. Blind tests revealed a correct identification of 93.9% of Pediculus humanus corporis (Linnaeus, 1758) and 98.4% of the other lice species collected in the field. This study demonstrated that MALDI-TOF MS could be successfully used for the identification of lice stored in alcohol for different lengths of time.

scholarly journals Rapid Classification of Clostridioides difficile Strains Using MALDI-TOF MS Peak-Based Assay in Comparison with PCR-Ribotyping

2021 ◽  
Vol 9 (3) ◽  
pp. 661
Author(s):  
Adriana Calderaro ◽  
Mirko Buttrini ◽  
Monica Martinelli ◽  
Benedetta Farina ◽  
Tiziano Moro ◽  
...  
Keyword(s):  
Ionization Time ◽  
Maldi Tof Ms ◽  
Maldi Tof ◽  
Flight Mass Spectrometry ◽  
Clostridioides Difficile ◽  
Pcr Ribotyping ◽  
Typing Methods ◽  
Set Up ◽  
Tof Ms

Typing methods are needed for epidemiological tracking of new emerging and hypervirulent strains because of the growing incidence, severity and mortality of Clostridioides difficile infections (CDI). The aim of this study was the evaluation of a typing Matrix-Assisted Desorption/Ionization-Time of Flight Mass Spectrometry (MALDI-TOF MS (T-MALDI)) method for the rapid classification of the circulating C. difficile strains in comparison with polymerase chain reaction (PCR)-ribotyping results. Among 95 C. difficile strains, 10 ribotypes (PR1–PR10) were identified by PCR-ribotyping. In particular, 93.7% of the isolates (89/95) were grouped in five ribotypes (PR1–PR5). For T-MALDI, two classifying algorithm models (CAM) were tested: the first CAM involved all 10 ribotypes whereas the second one only the PR1–PR5 ribotypes. Better performance was obtained using the second CAM: recognition capability of 100%, cross-validation of 96.6% and agreement of 98.4% (60 correctly typed strains, limited to PR1–PR5 classification, out of 61 examined strains) with PCR-ribotyping results. T-MALDI seems to represent an alternative to PCR-ribotyping in terms of reproducibility, set up time and costs, as well as a useful tool in epidemiological investigation for the detection of C. difficile clusters (either among CAM included ribotypes or out-of-CAM ribotypes) involved in outbreaks.

scholarly journals Matrix-assisted Laser Desorption Ionization-Time-of-Flight Mass Spectrometry (MALDI-TOF MS) as a Reliable Tool to Identify Species of Catalase-negative Gram-positive Cocci not Belonging to the Streptococcus Genus

2016 ◽  
Vol 10 (1) ◽  
pp. 202-208 ◽  
Author(s):  
Marisa Almuzara ◽  
Claudia Barberis ◽  
Viviana Rojas Velázquez ◽  
Maria Soledad Ramirez ◽  
Angela Famiglietti ◽  
...  
Keyword(s):  
Extraction Methods ◽  
Species Level ◽  
Ionization Time ◽  
Maldi Tof Ms ◽  
Genus Level ◽  
Maldi Tof ◽  
Flight Mass Spectrometry ◽  
Level Identification ◽  
Gram Positive Cocci ◽  
Tof Ms

Objective:To evaluate the performance of matrix-assisted laser desorption ionization-time-of-flight mass spectrometry (MALDI-TOF MS) by using 190 Catalase-negative Gram-Positive Cocci (GPC) clinical isolates.Methods:All isolates were identified by conventional phenotypic tests following the proposed scheme by Ruoff and Christensen and MALDI-TOF MS (Bruker Daltonics, BD, Bremen, Germany). Two different extraction methods (direct transfer formic acid method on spot and ethanol formic acid extraction method) and different cut-offs for genus/specie level identification were used. The score cut-offs recommended by the manufacturer (≥ 2.000 for species-level, 1.700 to 1.999 for genus level and <1.700 no reliable identification) and lower cut-off scores (≥1.500 for genus level, ≥ 1.700 for species-level and score <1.500 no reliable identification) were considered for identification. A minimum difference of 10% between the top and next closest score was required for a different genus or species.MALDI-TOF MS identification was considered correct when the result obtained from MS database agreed with the phenotypic identification result.When both methods gave discordant results, the 16S rDNA orsodAgenes sequencing was considered as the gold standard identification method. The results obtained by MS concordant with genes sequencing, although discordant with conventional phenotyping, were considered correct. MS results discordant with 16S orsodA identification were considered incorrect.Results:Using the score cut-offs recommended by the manufacturer, 97.37% and 81.05% were correctly identified to genus and species level, respectively. On the other hand, using lower cut-off scores for identification, 97.89% and 94.21% isolates were correctly identified to genus and species level respectively by MALDI-TOF MS and no significant differences between the results obtained with two extraction methods were obtained.Conclusion:The results obtained suggest that MALDI-TOF MS has the potential of being an accurate tool for Catalase-negative GPC identification even for those species with difficult diagnosis asHelcococcus,Abiotrophia,Granulicatella, among others. Nevertheless, expansion of the library, especially including more strains with different spectra on the same species might overcome potential “intraspecies” variability problems. Moreover, a decrease of the identification scores for species and genus-level identification must be considered since it may improve the MALDI-TOF MS accuracy.

scholarly journals Discrimination of Streptococcus equi subsp. equi and Streptococcus equi subsp. zooepidemicus using matrix-assisted laser desorption/ionization time-of-flight mass spectrometry

2017 ◽  
Vol 29 (5) ◽  
pp. 622-627 ◽  
Author(s):  
Rinosh J. Mani ◽  
Anil J. Thachil ◽  
Akhilesh Ramachandran
Keyword(s):  
Laser Desorption Ionization ◽  
Biochemical System ◽  
Ionization Time ◽  
Maldi Tof Ms ◽  
Maldi Tof ◽  
Flight Mass Spectrometry ◽  
Subspecies Level ◽  
Streptococcus Equi ◽  
Level Identification ◽  
Tof Ms

Accurate and timely identification of infectious etiologies is of great significance in veterinary microbiology, especially for critical diseases such as strangles, a highly contagious disease of horses caused by Streptococcus equi subsp. equi. We evaluated a matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) platform for use in species- and subspecies-level identification of S. equi isolates from horses and compared it with an automated biochemical system. We used 25 clinical isolates each of S. equi subsp. equi and S. equi subsp. zooepidemicus. Using the MALDI-TOF MS platform, it was possible to correctly identify all 50 isolates to the species level. Unique mass peaks were identified in the bacterial peptide mass spectra generated by MALDI-TOF MS, which can be used for accurate subspecies-level identification of S. equi. Mass peaks (mass/charge, m/ z) 6,751.9 ± 1.4 (mean ± standard deviation) and 5,958.1 ± 1.3 were found to be unique to S. equi subsp. equi and S. equi subsp. zooepidemicus, respectively. The automated biochemical system correctly identified 47 of 50 of the isolates to the species level as S. equi, whereas at the subspecies level, 24 of 25 S. equi subsp. equi isolates and 22 of 25 S. equi subsp. zooepidemicus isolates were correctly identified. Our results indicate that MALDI-TOF MS can be used for accurate species- and subspecies-level identification of S. equi.

scholarly journals Effect of Matrix-Assisted Laser Desorption Ionization–Time of Flight Mass Spectrometry (MALDI-TOF MS) Alone versus MALDI-TOF MS Combined with Real-Time Antimicrobial Stewardship Interventions on Time to Optimal Antimicrobial Therapy in Patients with Positive Blood Cultures

2017 ◽  
Vol 55 (5) ◽  
pp. 1437-1445 ◽  
Author(s):  
Maya Beganovic ◽  
Michael Costello ◽  
Sarah M. Wieczorkiewicz
Keyword(s):  
Real Time ◽  
Laser Desorption ◽  
Blood Cultures ◽  
Laser Desorption Ionization ◽  
Ionization Time ◽  
Maldi Tof Ms ◽  
Maldi Tof ◽  
Flight Mass Spectrometry ◽  
Tof Ms ◽  
Matrix Assisted Laser

ABSTRACT Matrix-assisted laser desorption ionization–time of flight mass spectrometry (MALDI-TOF MS) decreases the time to organism identification and improves clinical and financial outcomes. The purpose of this study was to evaluate the impact of MALDI-TOF MS alone versus MALDI-TOF MS combined with real-time, pharmacist-driven, antimicrobial stewardship (AMS) intervention on patient outcomes. This single-center, pre-post, quasiexperimental study evaluated hospitalized patients with positive blood cultures identified via MALDI-TOF MS combined with prospective AMS intervention compared to a control cohort with MALDI-TOF MS identification without AMS intervention. AMS intervention included: real-time MALDI-TOF MS pharmacist notification and prospective AMS provider feedback. The primary outcome was the time to optimal therapy (TTOT). A total of 252 blood cultures, 126 in each group, were included in the final analysis. MALDI-TOF MS plus AMS intervention significantly reduced the overall TTOT (75.17 versus 43.06 h; P < 0.001), the Gram-positive contaminant TTOT (48.21 versus 11.75 h; P < 0.001), the Gram-negative infection (GNI) TTOT (71.83 versus 35.98 h; P < 0.001), and the overall hospital length of stay (LOS; 15.03 versus 9.02 days; P = 0.021). The TTOT for Gram-positive infection (GPI) was improved (64.04 versus 41.61 h; P = 0.082). For GPI, the hospital LOS (14.64 versus 10.31 days; P = 0.002) and length of antimicrobial therapy 24.30 versus 18.97 days; P = 0.018) were reduced. For GNI, the time to microbiologic clearance (51.13 versus 34.51 h; P < 0.001), the hospital LOS (15.40 versus 7.90 days; P = 0.027), and the intensive care unit LOS (5.55 versus 1.19 days; P = 0.035) were reduced. To achieve optimal outcomes, rapid identification with MALDI-TOF MS combined with real-time AMS intervention is more impactful than MALDI-TOF MS alone.

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