scholarly journals Investigation of MALDI-TOF Mass Spectrometry for Assessing the Molecular Diversity of Campylobacter jejuni and Comparison with MLST and cgMLST: A Luxembourg One-Health Study

Diagnostics ◽  
2021 ◽  
Vol 11 (11) ◽  
pp. 1949
Author(s):  
Maureen Feucherolles ◽  
Morgane Nennig ◽  
Sören L. Becker ◽  
Delphine Martiny ◽  
Serge Losch ◽  
...  
Keyword(s):  
Random Forest ◽  
Health Study ◽  
Protein Profiles ◽  
Molecular Surveillance ◽  
Maldi Tof Ms ◽  
Maldi Tof ◽  
Early Signal ◽  
Routine Basis ◽  
Sequence Types ◽  
Tof Ms

There is a need for active molecular surveillance of human and veterinary Campylobacter infections. However, sequencing of all isolates is associated with high costs and a considerable workload. Thus, there is a need for a straightforward complementary tool to prioritize isolates to sequence. In this study, we proposed to investigate the ability of MALDI-TOF MS to pre-screen C. jejuni genetic diversity in comparison to MLST and cgMLST. A panel of 126 isolates, with 10 clonal complexes (CC), 21 sequence types (ST) and 42 different complex types (CT) determined by the SeqSphere+ cgMLST, were analysed by a MALDI Biotyper, resulting into one average spectra per isolate. Concordance and discriminating ability were evaluated based on protein profiles and different cut-offs. A random forest algorithm was trained to predict STs. With a 94% similarity cut-off, an AWC of 1.000, 0.933 and 0.851 was obtained for MLSTCC, MLSTST and cgMLST profile, respectively. The random forest classifier showed a sensitivity and specificity up to 97.5% to predict four different STs. Protein profiles allowed to predict C. jejuni CCs, STs and CTs at 100%, 93% and 85%, respectively. Machine learning and MALDI-TOF MS could be a fast and inexpensive complementary tool to give an early signal of recurrent C. jejuni on a routine basis.

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 Application of a MALDI-TOF analysis platform (ClinProTools) for rapid and preliminary report of MRSA sequence types in Taiwan

PeerJ ◽  
2018 ◽  
Vol 6 ◽  
pp. e5784 ◽  
Author(s):  
Hsin-Yao Wang ◽  
Frank Lien ◽  
Tsui-Ping Liu ◽  
Chun-Hsien Chen ◽  
Chao-Jung Chen ◽  
...  
Keyword(s):  
Infection Control ◽  
Discriminatory Power ◽  
Ionization Time ◽  
Maldi Tof Ms ◽  
Maldi Tof ◽  
Flight Mass Spectrometry ◽  
Taiwan Island ◽  
Analysis Platform ◽  
Sequence Types ◽  
Tof Ms

BackgroundThe accurate and rapid preliminarily identification of the types of methicillin-resistantStaphylococcus aureus(MRSA) is crucial for infection control. Currently, however, expensive, time-consuming, and labor-intensive methods are used for MRSA typing. By contrast, matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF MS) is a potential tool for preliminary lineage typing. The approach has not been standardized, and its performance has not been analyzed in some regions with geographic barriers (e.g., Taiwan Island).MethodsThe mass spectra of 306 MRSA isolates were obtained from multiple reference hospitals in Taiwan. The multilocus sequence types (MLST) of the isolates were determined. The spectra were analyzed for the selection of characteristic peaks by using the ClinProTools software. Furthermore, various machine learning (ML) algorithms were used to generate binary and multiclass models for classifying the major MLST types (ST5, ST59, and ST239) of MRSA.ResultsA total of 10 peaks with the highest discriminatory power (m/zrange: 2,082–6,594) were identified and evaluated. All the single peaks revealed significant discriminatory power during MLST typing. Moreover, the binary and multiclass ML models achieved sufficient accuracy (82.80–94.40% for binary models and >81.00% for multiclass models) in classifying the major MLST types.ConclusionsA combination of MALDI-TOF MS analysis and ML models is a potentially accurate, objective, and efficient tool for infection control and outbreak investigation.

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.

Evaluation of changes in serum protein profiles during neoadjuvant chemotherapy in HER2-positive breast cancer using an LC-MALDI-TOF/MS procedure

PROTEOMICS ◽  
2010 ◽  
Vol 10 (19) ◽  
pp. 3525-3532 ◽  
Author(s):  
Chafika Mazouni ◽  
Keith Baggerly ◽  
David Hawke ◽  
Spyros Tsavachidis ◽  
Fabrice André ◽  
...  
Keyword(s):  
Breast Cancer ◽  
Neoadjuvant Chemotherapy ◽  
Serum Protein ◽  
Protein Profiles ◽  
Her2 Positive ◽  
Maldi Tof Ms ◽  
Her2 Positive Breast Cancer ◽  
Maldi Tof ◽  
Tof Ms ◽  
Positive Breast Cancer

scholarly journals Overestimated discriminatory power of MALDI-TOF mass spectrometry for typing of carbapenem-resistant Klebsiella pneumoniae clones

2019 ◽  
Vol 147 ◽  
Author(s):  
Fei Jiang ◽  
Ziyan Kong ◽  
Chen Cheng ◽  
Haiquan Kang ◽  
Bing Gu ◽  
...  
Keyword(s):  
Klebsiella Pneumoniae ◽  
Taxonomic Diversity ◽  
Discriminatory Power ◽  
Adjusted Rand Index ◽  
Maldi Tof Ms ◽  
Maldi Tof ◽  
Carbapenem Resistant ◽  
Typing Methods ◽  
Sequence Types ◽  
Tof Ms

Abstract Homology surveillance of carbapenem-resistant Klebsiella pneumoniae (CRKP) is critical to monitor and prevent outbreaks of nosocomial infections. In the present study, a matrix-assisted laser desorption/ionisation-time of flight (MALDI-TOF MS)-based method was evaluated as a rapid tool for typing CRKP in comparison with pulsed-field gel electrophoresis (PFGE) and multi locus sequence typing (MLST). Drug-resistant phenotypes and genotypes of 44 CRKP isolates were detected by microdilution broth method and polymerase chain reaction, and typed by PFGE, MLST and MALDI-TOF MS. Simpson's Index of Diversity was used to evaluate taxonomic diversity, Adjusted Rand Index (ARI) for congruence between the typing methods and Wallace coefficients (W) for the ability of either method to predict each other. Forty-four CRKP isolates of 15 sequence types (STs) produced either NDM-1 (n = 16), NDM-5 (n = 9) or KPC-2 (n = 19) carbapenemases. PFGE differentiated these isolates into 16 distinct types, and two deoxyribonucleic acid profiles were assigned to ST337 and ST11, respectively. MALDI-TOF MS failed to clearly delineate between clusters on dendrograms based on principal components analysis and main spectrum profile. The chosen parameters resulted in a maximum ARI of 0.310 (95% CI 0.088–0.531) between MALDI-TOF MS typing and the PFGE reference, indicating a low ability of the former to correctly identify related isolates. Likewise, the maximum W coefficient of 0.367 (95% CI 0.203–0.532) showed that MALDI-TOF MS had a lower predictive power than PFGE. We conclude that MALDI-TOF MS lacks the discriminatory power necessary for clone assignment of CRKP isolates and consequently cannot be considered as a rapid and creditable method for this purpose.

Optimization of analytical and pre-analytical conditions for MALDI-TOF-MS human urine protein profiles

2010 ◽  
Vol 51 (4) ◽  
pp. 907-914 ◽  
Author(s):  
C.D. Calvano ◽  
A. Aresta ◽  
M. Iacovone ◽  
G.E. De Benedetto ◽  
C.G. Zambonin ◽  
...  
Keyword(s):  
Human Urine ◽  
Protein Profiles ◽  
Urine Protein ◽  
Maldi Tof Ms ◽  
Maldi Tof ◽  
Tof Ms

scholarly journals USE OF MALDI-TOF MS METHOD FOR SPECIES DIFFERENTIATION OF NEMATODES (BY EXAMPLE OF STUDYING PROTEIN PROFILES OF ASCARIDATE AND DIROFILARIA)

2020 ◽  
pp. 267-275
Author(s):  
Nagorniy ◽  
A. Aleshukina ◽  
I. Aleshukina ◽  
Ermakova
Keyword(s):  
Proteomic Analysis ◽  
Protein Profile ◽  
Species Differentiation ◽  
Protein Profiles ◽  
Maldi Tof Ms ◽  
Maldi Tof ◽  
Spectral Peaks ◽  
Spectral Profiles ◽  
Tof Ms

The article presents the results of studying protein profiles of nematodes relevant for the south of Russia (dirofilaria and ascaridate) using proteomic analysis based on MALDI-TOF MS. Analysis of the protein extracts of dirofilaria and ascaridate showed spectra with high-intensity peaks in the range of 2–20 kDa, the quality of the spectra and the intensities of the spectral peaks were consistent for all samples of the same species. It was noted that reliably frequent peaks were observed in the spectra obtained from various dirofilariae (D. repens and D. immitis) in the range from 3400 to 6000 kDa, that characterize the entire genus of nematodes. In the range above 6000 kDa, the spectra differed by representative peaks, which allowed us to differentiate one species from another according to the protein profile. The spectral profiles obtained from the ascarid A. suum and A. lumbricoi proteins, unlike dirofilaria, showed almost complete homology of graphic images in the m/z range from 3000 kDa to 15 000 kDa. At the same time, protein peaks in the range of 3000–7300 kDa, typical for the entire genus Ascaris, are constant. Three main peaks in both species were found in m/z 13 000, 13 400 and 14 400. Thus, the method of proteomic analysis based on MALDI-TOFF MS can serve as an effective tool in studies of the taxonomic identification of the pathogen.

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