scholarly journals MALDI-TOF MS and genomic analysis can make the difference in the clarification of canine brucellosis outbreaks

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
David Attuy Vey da Silva ◽  
Holger Brendebach ◽  
Josephine Grützke ◽  
Ralf Dieckmann ◽  
Rodrigo Martins Soares ◽  
...  
Keyword(s):  
High Throughput Sequencing ◽  
Intact Cell ◽  
Clinical Manifestations ◽  
Mass Spectrometry Analysis ◽  
Reference Database ◽  
Polymorphism Analysis ◽  
Maldi Tof Ms ◽  
Maldi Tof ◽  
Canine Brucellosis ◽  
Tof Ms

Abstract Brucellosis is one of the most common bacterial zoonoses worldwide affecting not only livestock and wildlife but also pets. Canine brucellosis is characterized by reproductive failure in dogs. Human Brucella canis infections are rarely reported but probably underestimated due to insufficient diagnostic surveillance. To improve diagnostics, we investigated dogs in a breeding kennel that showed clinical manifestations of brucellosis and revealed positive blood cultures. As an alternative to the time-consuming and hazardous classical identification procedures, a newly developed species-specific intact-cell matrix-assisted laser desorption/ionization–time of flight mass spectrometry analysis was applied, which allowed for rapid identification of B. canis and differentiation from closely related B. suis biovar 1. High-throughput sequencing and comparative genomics using single nucleotide polymorphism analysis clustered our isolates together with canine and human strains from various Central and South American countries in a distinct sub-lineage. Hence, molecular epidemiology clearly defined the outbreak cluster and demonstrated the endemic situation in South America. Our study illustrates that MALDI-TOF MS analysis using a validated in-house reference database facilitates rapid B. canis identification at species level. Additional whole genome sequencing provides more detailed outbreak information and leads to a deeper understanding of the epidemiology of canine brucellosis.

Black aspergilli: A remaining challenge in fungal taxonomy?

2018 ◽  
Vol 57 (6) ◽  
pp. 773-780 ◽  
Author(s):  
Elizabet D’hooge ◽  
Pierre Becker ◽  
Dirk Stubbe ◽  
Anne-Cécile Normand ◽  
Renaud Piarroux ◽  
...  
Keyword(s):  
Antifungal Susceptibility ◽  
Identification Accuracy ◽  
Clinical Isolates ◽  
Reference Database ◽  
Data Set ◽  
Ionization Time ◽  
Maldi Tof Ms ◽  
Maldi Tof ◽  
Flight Mass Spectrometry ◽  
Tof Ms

AbstractAspergillus section Nigri is a taxonomically difficult but medically and economically important group. In this study, an update of the taxonomy of A. section Nigri strains within the BCCM/IHEM collection has been conducted. The identification accuracy of matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) was tested and the antifungal susceptibilities of clinical isolates were evaluated. A total of 175 strains were molecularly analyzed. Three regions were amplified (ITS, benA, and caM) and a multi-locus phylogeny of the combined loci was created by using maximum likelihood analysis. The in-house MALDI-TOF MS reference database was extended and an identification data set of 135 strains was run against a reference data set. Antifungal susceptibility was tested for voriconazole, itraconazole, and amphotericin B, using the EUCAST method. Phylogenetic analysis revealed 18 species in our data set. MALDI-TOF MS was able to distinguish between A. brasiliensis, A. brunneoviolaceus, A. neoniger, A. niger, A. tubingensis, and A. welwitschiae of A. sect. Nigri. In the routine clinical lab, isolates of A. sect. Nigri are often identified as A. niger. However, in the clinical isolates of our data set, A. tubingensis (n = 35) and A. welwitschiae (n = 34) are more common than A. niger (n = 9). Decreased antifungal susceptibility to azoles was observed in clinical isolates of the /tubingensis clade. This emphasizes the importance of identification up to species level or at least up to clade level in the clinical lab. Our results indicate that MALDI-TOF MS can be a powerful tool to replace classical morphology.

scholarly journals Novel Method for Reliable Identification of Siccibacter and Franconibacter Strains: from “Pseudo-Cronobacter” to New Enterobacteriaceae Genera

2017 ◽  
Vol 83 (13) ◽  
Author(s):  
Barbora Svobodová ◽  
Jiří Vlach ◽  
Petra Junková ◽  
Ludmila Karamonová ◽  
Martina Blažková ◽  
...  
Keyword(s):  
Intact Cell ◽  
Foodborne Pathogen ◽  
Principal Component ◽  
Powdered Infant Formula ◽  
Content Type ◽  
Reliable Identification ◽  
Maldi Tof Ms ◽  
Maldi Tof ◽  
Maldi Biotyper ◽  
Tof Ms

ABSTRACT In the last decade, strains of the genera Franconibacter and Siccibacter have been misclassified as first Enterobacter and later Cronobacter. Because Cronobacter is a serious foodborne pathogen that affects premature neonates and elderly individuals, such misidentification may not only falsify epidemiological statistics but also lead to tests of powdered infant formula or other foods giving false results. Currently, the main ways of identifying Franconibacter and Siccibacter strains are by biochemical testing or by sequencing of the fusA gene as part of Cronobacter multilocus sequence typing (MLST), but in relation to these strains the former is generally highly difficult and unreliable while the latter remains expensive. To address this, we developed a fast, simple, and most importantly, reliable method for Franconibacter and Siccibacter identification based on intact-cell matrix-assisted laser desorption ionization–time of flight mass spectrometry (MALDI-TOF MS). Our method integrates the following steps: data preprocessing using mMass software; principal-component analysis (PCA) for the selection of mass spectrum fingerprints of Franconibacter and Siccibacter strains; optimization of the Biotyper database settings for the creation of main spectrum projections (MSPs). This methodology enabled us to create an in-house MALDI MS database that extends the current MALDI Biotyper database by including Franconibacter and Siccibacter strains. Finally, we verified our approach using seven previously unclassified strains, all of which were correctly identified, thereby validating our method. IMPORTANCE We show that the majority of methods currently used for the identification of Franconibacter and Siccibacter bacteria are not able to properly distinguish these strains from those of Cronobacter. While sequencing of the fusA gene as part of Cronobacter MLST remains the most reliable such method, it is highly expensive and time-consuming. Here, we demonstrate a cost-effective and reliable alternative that correctly distinguishes between Franconibacter, Siccibacter, and Cronobacter bacteria and identifies Franconibacter and Siccibacter at the species level. Using intact-cell MALDI-TOF MS, we extend the current MALDI Biotyper database with 11 Franconibacter and Siccibacter MSPs. In addition, the use of our approach is likely to lead to a more reliable identification scheme for Franconibacter and Siccibacter strains and, consequently, a more trustworthy epidemiological picture of their involvement in disease.

scholarly journals Reagent-Free Identification of Clinical Yeasts by Use of Attenuated Total Reflectance Fourier Transform Infrared Spectroscopy

2019 ◽  
Vol 57 (5) ◽  
Author(s):  
Lisa M. T. Lam ◽  
Philippe J. Dufresne ◽  
Jean Longtin ◽  
Jacqueline Sedman ◽  
Ashraf A. Ismail
Keyword(s):  
Fourier Transform ◽  
Ftir Spectroscopy ◽  
Fourier Transform Infrared ◽  
Attenuated Total Reflectance ◽  
Reference Database ◽  
Accurate Identification ◽  
Total Reflectance ◽  
Maldi Tof Ms ◽  
Maldi Tof ◽  
Tof Ms

ABSTRACT Invasive fungal infections by opportunistic yeasts have increased concomitantly with the growth of an immunocompromised patient population. Misidentification of yeasts can lead to inappropriate antifungal treatment and complications. Attenuated total reflectance Fourier transform infrared (ATR-FTIR) spectroscopy is a promising method for rapid and accurate identification of microorganisms. ATR-FTIR spectroscopy is a standalone, inexpensive, reagent-free technique that provides results within minutes after initial culture. In this study, a comprehensive spectral reference database of 65 clinically relevant yeast species was constructed and tested prospectively on spectra recorded (from colonies taken from culture plates) for 318 routine yeasts isolated from various body fluids and specimens received from 38 microbiology laboratories over a 4-month period in our clinical laboratory. ATR-FTIR spectroscopy attained comparable identification performance with matrix-assisted laser desorption ionization–time of flight mass spectrometry (MALDI-TOF MS). In a preliminary validation of the ATR-FTIR method, correct identification rates of 100% and 95.6% at the genus and species levels, respectively, were achieved, with 3.5% unidentified and 0.9% misidentified. By expanding the number of spectra in the spectral reference database for species for which isolates could not be identified or had been misidentified, we were able to improve identification at the species level to 99.7%. Thus, ATR-FTIR spectroscopy provides a new standalone method that can rival MALDI-TOF MS for the accurate identification of a broad range of medically important yeasts. The simplicity of the ATR-FTIR spectroscopy workflow favors its use in clinical laboratories for timely and low-cost identification of life-threatening yeast strains for appropriate treatment.

scholarly journals Rapid classification and prediction of COVID-19 severity by MALDI-TOF mass spectrometry analysis of serum peptidome

2020 ◽  
Author(s):  
Rosa M. Gomila ◽  
Gabriel Martorell ◽  
Pablo A. Fraile-Ribot ◽  
Antonio Doménech-Sánchez ◽  
Antonio Oliver ◽  
...  
Keyword(s):  
Machine Learning ◽  
Mass Spectrometry ◽  
Favourable Outcome ◽  
Mass Spectrometry Analysis ◽  
Learning Approaches ◽  
Maldi Tof Ms ◽  
Spectrometry Analysis ◽  
Maldi Tof ◽  
Critical Patients ◽  
Tof Ms

ABSTRACTClassification and early detection of severe COVID-19 patients is urgently required to establish an effective treatment. Here, 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 in a clinical setting. We used this technology to analyse the mass spectra profiles of the sera from 80 COVID-19 patients, clinically classified as mild (33), severe (26) and critical (21), and 20 healthy controls. We found a clear variability of the serum peptidome profile depending on COVID-19 severity. Seventy-eight peaks were significantly different and 12 at least four fold more intense in the set of critical patients than in the mild ones. Analysis of the resulting matrix of peak intensities by machine learning approaches classified severe (severe and critical) and non-severe (mild) patients with a 90% of accuracy. Furthermore, machine learning predicted correctly the favourable outcome of the severe patients in 85% of the cases and the unfavourable in 38% of the cases. Finally, liquid chromatography mass spectrometry analysis of sera identified five proteins that were significantly upregulated in the critical patients. They included serum amyloid proteins A1 and A2, which probably yielded the most intense peaks with m/z 11,530 and 11,686 detected by MALDI-TOF MS.In summary, we demonstrated the potential of the MALDI-TOF MS as a bench to bedside technology to aid clinicians in their decisions to classify COVID-19 patients and predict their evolution.

scholarly journals Understanding the chemical basis for the preferential ionization of specific biomolecules in mass spectrometry analysis of microbial cells

2019 ◽  
Author(s):  
Wenfa Ng
Keyword(s):  
Mass Spectrometry ◽  
Mass Spectra ◽  
Mass Spectrometry Analysis ◽  
Chemical Pretreatment ◽  
Maldi Tof Ms ◽  
Spectrometry Analysis ◽  
Chemical Basis ◽  
Maldi Tof ◽  
Different Types ◽  
Tof Ms

Mass spectrometry-enabled microbial identification has successfully demonstrated the feasibility of using profiled biomolecules for identifying microorganisms based on a chemometric or proteome database search approach. However, mechanisms driving the preferential ionization and detection of particular biomolecules in various types of mass spectrometry remain poorly understood. Specifically, mass spectra obtained from different microbial species remain poorly annotated with respect to the specific types of biomolecules accounting for the peaks. For example, while ribosomal proteins are known to be a significant class of biomolecules that could partially account for the profiled mass peaks in mass spectra of microorganisms, other classes of proteins and biomolecules remain poorly annotated. This raises the important question of how different mass spectrometry approaches ionize different types of biomolecules from a cellular matrix. Specifically, mass spectra of microorganisms reveal that only a couple of mass peaks could capture the phylogeny of a species. However, the proteome of a cell is much larger and more complicated, and yet is not fully profiled by different types of mass spectrometry methods. For example, electrospray ionization mass spectrometry (ESI-MS) and matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) could only provide a small snapshot of the entire bacterial proteome. It could be argued that different mass spectrometry methods provide complementary views of a particular proteome. However, the question remains, how do proteins and biomolecules interact with the different sample preparation and mass spectrometry analysis methods for generating an ion cloud for separation in a mass spectrometer? Thus, efforts could be directed towards understanding how different types of proteins could be preferentially ionized by MALDI-TOF MS. Specifically, different reagents could be used to perform chemical pretreatment on the proteome, which would subsequently be analyzed by mass spectrometry. Thus, a correlative map between types of chemical pretreatment used and the corresponding mass spectra could be obtained. Collectively, knowledge gleaned from the research would illuminate the chemical basis by which specific biomolecules are preferentially ionized under particular conditions, which would inform the development of strategies for increasing the subset of biomolecules ionized from a cellular proteome. Such chemical rules would also aid in the interpretation of mass spectra obtained, particularly in understanding the biological context of the experiment. Overall, the key goal of this research is to help answer the question: what is the biological basis and context of the mass spectrum obtained from cells?

scholarly journals „Intact Cell”︁ MALDI-TOF MS: Monitoring von Zellstress in CHO-Zellkultivierungsansätzen

2014 ◽  
Vol 86 (9) ◽  
pp. 1581-1581
Author(s):  
S. Schwamb ◽  
M. Hafner ◽  
C. Hopf ◽  
P. Wiedemann
Keyword(s):  
Intact Cell ◽  
Maldi Tof Ms ◽  
Maldi Tof ◽  
Tof Ms

scholarly journals Understanding the chemical basis for the preferential ionization of specific biomolecules in mass spectrometry analysis of microbial cells

2019 ◽  
Author(s):  
Wenfa Ng
Keyword(s):  
Mass Spectrometry ◽  
Mass Spectra ◽  
Mass Spectrometry Analysis ◽  
Chemical Pretreatment ◽  
Maldi Tof Ms ◽  
Spectrometry Analysis ◽  
Chemical Basis ◽  
Maldi Tof ◽  
Different Types ◽  
Tof Ms

Mass spectrometry-enabled microbial identification has successfully demonstrated the feasibility of using profiled biomolecules for identifying microorganisms based on a chemometric or proteome database search approach. However, mechanisms driving the preferential ionization and detection of particular biomolecules in various types of mass spectrometry remain poorly understood. Specifically, mass spectra obtained from different microbial species remain poorly annotated with respect to the specific types of biomolecules accounting for the peaks. For example, while ribosomal proteins are known to be a significant class of biomolecules that could partially account for the profiled mass peaks in mass spectra of microorganisms, other classes of proteins and biomolecules remain poorly annotated. This raises the important question of how different mass spectrometry approaches ionize different types of biomolecules from a cellular matrix. Specifically, mass spectra of microorganisms reveal that only a couple of mass peaks could capture the phylogeny of a species. However, the proteome of a cell is much larger and more complicated, and yet is not fully profiled by different types of mass spectrometry methods. For example, electrospray ionization mass spectrometry (ESI-MS) and matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) could only provide a small snapshot of the entire bacterial proteome. It could be argued that different mass spectrometry methods provide complementary views of a particular proteome. However, the question remains, how do proteins and biomolecules interact with the different sample preparation and mass spectrometry analysis methods for generating an ion cloud for separation in a mass spectrometer? Thus, efforts could be directed towards understanding how different types of proteins could be preferentially ionized by MALDI-TOF MS. Specifically, different reagents could be used to perform chemical pretreatment on the proteome, which would subsequently be analyzed by mass spectrometry. Thus, a correlative map between types of chemical pretreatment used and the corresponding mass spectra could be obtained. Collectively, knowledge gleaned from the research would illuminate the chemical basis by which specific biomolecules are preferentially ionized under particular conditions, which would inform the development of strategies for increasing the subset of biomolecules ionized from a cellular proteome. Such chemical rules would also aid in the interpretation of mass spectra obtained, particularly in understanding the biological context of the experiment. Overall, the key goal of this research is to help answer the question: what is the biological basis and context of the mass spectrum obtained from cells?

scholarly journals Campylobacter fetus subsp. testudinum subsp. nov., isolated from humans and reptiles

2014 ◽  
Vol 64 (Pt_9) ◽  
pp. 2944-2948 ◽  
Author(s):  
Collette Fitzgerald ◽  
Zheng chao Tu ◽  
Mary Patrick ◽  
Tracy Stiles ◽  
Andy J. Lawson ◽  
...  
Keyword(s):  
Type Species ◽  
Rrna Gene ◽  
Polymorphism Analysis ◽  
Content Type ◽  
Maldi Tof Ms ◽  
Link Type ◽  
Maldi Tof ◽  
Campylobacter Fetus ◽  
Phenotypic Tests ◽  
Tof Ms

A polyphasic study was undertaken to determine the taxonomic position of 13 Campylobacter fetus -like strains from humans (n = 8) and reptiles (n = 5). The results of matrix-assisted laser desorption ionization time-of-flight (MALDI-TOF) MS and genomic data from sap analysis, 16S rRNA gene and hsp60 sequence comparison, pulsed-field gel electrophoresis, amplified fragment length polymorphism analysis, DNA–DNA hybridization and whole genome sequencing demonstrated that these strains are closely related to C. fetus but clearly differentiated from recognized subspecies of C. fetus . Therefore, this unique cluster of 13 strains represents a novel subspecies within the species C. fetus , for which the name Campylobacter fetus subsp. testudinum subsp. nov. is proposed, with strain 03-427T ( = ATCC BAA-2539T = LMG 27499T) as the type strain. Although this novel taxon could not be differentiated from C. fetus subsp. fetus and C. fetus subsp. venerealis using conventional phenotypic tests, MALDI-TOF MS revealed the presence of multiple phenotypic biomarkers which distinguish Campylobacter fetus subsp. testudinum subsp. nov. from recognized subspecies of C. fetus .

Evaluation of serum profiles changes after neoadjuvant chemotherapy for breast cancer using MALDI-TOF/MS procedure

2009 ◽  
Vol 27 (15_suppl) ◽  
pp. e22072-e22072
Author(s):  
D. Hawke ◽  
C. Mazouni ◽  
F. André ◽  
K. Baggerly ◽  
K. Baggerly ◽  
...  
Keyword(s):  
Breast Cancer ◽  
Mass Spectrometry ◽  
Neoadjuvant Chemotherapy ◽  
Residual Disease ◽  
Differentially Expressed ◽  
Mass Spectrometry Analysis ◽  
Her2 Positive ◽  
Maldi Tof Ms ◽  
Maldi Tof ◽  
Tof Ms

e22072 Evaluation of serum profiles changes after neoadjuvant chemotherapy for breast cancer using MALDI-TOF / MS procedure. Background: Response to primary chemotherapy (CT) for breast cancer is heterogeneous among patients and a more tailored treatment would be beneficial in term of reducing exposure to an unnecessary toxicity and optimization of response rates. Mass spectrometry analysis of serum might be helpful in detecting specific changes in response to primary CT. Methods: An applied Biosystems 4700 Proteomics Analyzer matrix-assisted laser desorption/ionization time-of-flight (MALDI-TOF) mass spectrometer was used. A breast cancer cohort of 78 sera samples from 39 HER2 positive patients consisting of matched pretreatment and (6 months) posttreatment samples was used. Blood samples were collected serially before each treatment cycle every 3 weeks of neoadjuvant CT. Samples were divided into those who achieved pathological complete response (pCR, n= 20) and those who had residual disease (RD, n=19). Low-mass differentially expressed peptides were identified using MALDI-TOF/TOF. Results: This procedure yielded a total of 2329 and 3152 peaks respectively, for the responders and non-responders. Biological variation analysis revealed a total of 32 peaks for responders and 643 peaks for non-responders to be differentially regulated with a false discovery rate less than 20%. A total of 8 differentially expressed proteins were identified from their peptides after digestion and LC-MALDI-TOF/TOF. Four in tumors with pCR (AFM, C3, hemopexin, SAP) and four proteins in the RD group were identified (AP1, hemopexin, Complement B, amyloid P component) Conclusions: Our study suggests that MALDI mass spectrometry may be used to predict the tumor response to neoadjuvant chemotherapy. Proteomic analysis may be useful in developing tailored chemotherapy for breast cancer. No significant financial relationships to disclose.

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