scholarly journals Identification of cereulide producingBacillus cereusby MALDI-TOF MS

2018 ◽  
Author(s):  
Sebastian Ulrich ◽  
Christoph Gottschalk ◽  
Richard Dietrich ◽  
Erwin Märtlbauer ◽  
Manfred Gareis
Keyword(s):  
Causative Agent ◽  
Food Chain ◽  
Reliable Method ◽  
Correct Identification ◽  
Maldi Tof Ms ◽  
Maldi Tof ◽  
Heat Stable ◽  
Food Borne ◽  
Reliable Methods ◽  
Tof Ms

AbstractTheBacillus(B.)cereusgroup is genetically highly homogenous and consists of nine recognized species which are present worldwide.B. cereussensu stricto play an important role in food-borne diseases by producing different toxins. Yet, only a small percentage ofB. cereusstrains are able to produce the heat stable depsipeptide cereulide, the causative agent of emetic food poisonings. To minimize the entry of emeticB. cereusinto the food chain, food business operators are dependent on efficient and reliable methods enabling the differentiation between emetic and non-emetic strains. Currently, only time-consuming cell bioassays, molecular methods and tandem mass spectrometry are available for this purpose. Thus, the aim of the present study was to establish a fast and reliable method for the differentiation between emetic and non-emetic strains by MALDI-TOF MS. Selected isolates/strains of theB. cereusgroup (total n=110, i.e. emetic n=45, non-emetic n=65) were cultured on sheep blood agar for 48h.Subsequently, the cultures were directly analyzed by MALDI-TOF MS without prior extraction steps (direct smear method). The samples were measured in linear positive ionization mode in the mass range ofm/z800 - 1,800 Da. Using ClinProTools 3.0 statistical software and flex analyst, a differentiation between emetic and non-emetic isolates was possible with a rate of correct identification of 99.1 % by means of the evaluation of two specific biomarkers (m/z1171 and 1187 Da).ImportanceBacillus(B.)cereusplays an important role in food-borne diseases due to the production of different toxins, e.g. the heat stable depsipeptide cereulide. Only a small number ofB. cereusstrains are able to produce this toxin, the causative agent of emetic food poisonings. To minimize the entry of emeticB. cereusinto the food chain, food business operators require efficient and reliable methods enabling the differentiation between emetic and non-emetic strains. The aim of the present study was to develop a fast and reliable method for the differentiation between emetic and non-emetic strains by MALDI-TOF MS. A differentiation between emetic and non-emetic isolates was possible with a rate of correct identification of 99.1 % by means of the evaluation of two specific biomarkers (m/z1171 and 1187 Da).

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 analysis of MALDI-TOF MS in rapid identification of anaerobic bacteria

2019 ◽  
Author(s):  
Ying Li ◽  
Mingzhu Shan ◽  
Zuobin Zhu ◽  
Xuhua Mao ◽  
Mingju Yan ◽  
...  
Keyword(s):  
Fixed Effects ◽  
Meta Analysis ◽  
Anaerobic Bacteria ◽  
Identification Accuracy ◽  
P Value ◽  
Correct Identification ◽  
Maldi Tof Ms ◽  
Analytical Technique ◽  
Maldi Tof ◽  
Tof Ms

Abstract BACKGROUND: Matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS) has been rapidly developed and widely used as an analytical technique in the clinical laboratories with high accuracy in the identification of microorganisms. METHOD: This study was designed to evaluate MALDI-TOF MS for identification of clinical pathogenic anaerobes. RESULT: Twenty-eight studies covering 6685 strains of anaerobic bacteria were included in this meta-analysis. Fixed-effects models based on the P-value and the I-squared were used for meta-analysis to consider the possibility of heterogeneity between studies. Statistical analyses were performed by using STATA 12.0. Results shown that the identification accuracy of MALDI-TOF MS at species was 84% (I2 = 98.0%, P < 0.1), genus was 92% (I2 = 96.6%, P < 0.1). Thereinto, the identification accuracy of Bacteroides was the highest at 96% with a 95% CI of 95% to 97%. Next were Lactobacillus spp., Parabacteroides spp., Clostridium spp., Propionibacterium spp., Prevotella spp., Veillonella spp. and Peptostreptococcus spp., and their correct identification rates were all above 90%, while the accuracy of rare anaerobic bacteria was lower. Meanwhile, the overall capabilitys of two MALDI-TOF MS systems were different. The identification accuracy rate of VITEK MS was 90%, compared to 86% by the MALDI biotyper system. CONCLUSON: In summary, our research showed that MALDI-TOF-MS was satisfactory in the identification of genus in clinical pathogenic anaerobic bacteria. However, this method still suffered from different drawbacks in the identification of the rare anaerobes and species levels of common anaerobic bacteria.

scholarly journals MALDI-TOF mass spectrometry for the identification of freshwater snails from Senegal, including intermediate hosts of schistosomes

2021 ◽  
Vol 15 (9) ◽  
pp. e0009725
Author(s):  
Fatima Zohra Hamlili ◽  
Fatou Thiam ◽  
Maureen Laroche ◽  
Adama Zan Diarra ◽  
Souleymane Doucouré ◽  
...  
Keyword(s):  
Neglected Diseases ◽  
Freshwater Snails ◽  
Snail Species ◽  
Correct Identification ◽  
Intermediate Hosts ◽  
Biomphalaria Pfeifferi ◽  
Bulinus Truncatus ◽  
Maldi Tof Ms ◽  
Maldi Tof ◽  
Tof Ms

Freshwater snails of the genera Biomphalaria, Bulinus, and Oncomelania are intermediate hosts of schistosomes that cause human schistosomiasis, one of the most significant infectious neglected diseases in the world. Identification of freshwater snails is usually based on morphology and, potentially, DNA-based methods, but these have many drawbacks that hamper their use. MALDI-TOF MS has revolutionised clinical microbiology and has emerged in the medical entomology field. This study aims to evaluate MALDI-TOF MS profiling for the identification of both frozen and ethanol-stored snail species using protein extracts from different body parts. A total of 530 field specimens belonging to nine species (Biomphalaria pfeifferi, Bulinus forskalii, Bulinus senegalensis, Bulinus truncatus, Bulinus globosus, Bellamya unicolor, Cleopatra bulimoides, Lymnaea natalensis, Melanoides tuberculata) and 89 laboratory-reared specimens, including three species (Bi. pfeifferi, Bu. forskalii, Bu. truncatus) were used for this study. For frozen snails, the feet of 127 field and 74 laboratory-reared specimens were used to validate the optimised MALDI-TOF MS protocol. The spectral analysis yielded intra-species reproducibility and inter-species specificity which resulted in the correct identification of all the specimens in blind queries, with log-score values greater than 1.7. In a second step, we demonstrated that MALDI-TOF MS could also be used to identify ethanol-stored snails using proteins extracted from the foot using a specific database including a large number of ethanol preserved specimens. This study shows for the first time that MALDI-TOF MS is a reliable tool for the rapid identification of frozen and ethanol-stored freshwater snails without any malacological expertise.

scholarly journals Application of MALDI-TOF MS to rapid identification of anaerobic bacteria

2019 ◽  
Author(s):  
Ying Li ◽  
Mingzhu Shan ◽  
Zuobin Zhu ◽  
Xuhua Mao ◽  
Mingju Yan ◽  
...  
Keyword(s):  
Fixed Effects ◽  
Meta Analysis ◽  
Anaerobic Bacteria ◽  
Identification Accuracy ◽  
P Value ◽  
Correct Identification ◽  
Maldi Tof Ms ◽  
Analytical Technique ◽  
Maldi Tof ◽  
Tof Ms

Abstract Matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS) has been rapidly developed and widely used as an analytical technique in clinical laboratories with high accuracy in microorganism identification. OBJECTIVE: To validate the efficacy of MALDI-TOF MS in identification of clinical pathogenic anaerobes. METHODS: Twenty-eight studies covering 6685 strains of anaerobic bacteria were included in this meta-analysis. Fixed-effects models based on the P -value and the I-squared were used for meta-analysis to consider the possibility of heterogeneity between studies. Statistical analyses were performed by using STATA 12.0. RESULTS : The identification accuracy of MALDI-TOF MS was 84% for species (I 2 = 98.0%, P < 0.1), and 92% for genus (I 2 = 96.6%, P < 0.1). Thereinto, the identification accuracy of Bacteroides was the highest at 96% with a 95% CI of 95-97%, followed by Lactobacillus spp., Parabacteroides spp., Clostridium spp., Propionibacterium spp., Prevotella spp., Veillonella spp. and Peptostreptococcus spp., and their correct identification rates were all above 90%, while the accuracy of rare anaerobic bacteria was relatively low. Meanwhile, the overall capabilities of two MALDI-TOF MS systems were different. The identification accuracy rate was 90% for VITEK MS vs . 86% for MALDI biotyper system. CONCLUSIONS: Our research showed that MALDI-TOF-MS was satisfactory in genus identification of clinical pathogenic anaerobic bacteria. However, this method still suffers from different drawbacks in precise identification of rare anaerobe and species levels of common anaerobic bacteria. Key words : MALDI-TOF MS , anaerobec, bacteria identification

Discrimination among Cryptococcus deneoformans, C. neoformans and interspecies hybrids using MALDI-TOF Mass Spectrometry

2020 ◽  
Author(s):  
Margarita Estreya Zvezdanova ◽  
Manuel J. Arroyo ◽  
Gema Méndez ◽  
Jesús Guinea ◽  
Luis Mancera ◽  
...  
Keyword(s):  
Hierarchical Clustering ◽  
Support Vector ◽  
Correct Identification ◽  
Differential Analysis ◽  
Maldi Tof Ms ◽  
Maldi Tof ◽  
Interspecies Hybrids ◽  
Protein Spectra ◽  
Correct Discrimination ◽  
Tof Ms

ABSTRACTBackgroundDifferentiation of the species within the Cryptococcus neoformans complex (C. deneoformans, C. neoformans and C. neoformans interspecies hybrids –C. deneoformans x C. neoformans-) is important to define the epidemiology of the infection.ObjectivesIn this study we attempted the discrimination of three C. neoformans species using MALDI-TOF MS coupled with an in-house library.MethodsAll Cryptococcus spp. isolates were identified by AFLP markers. An in-house database was constructed 26 well characterized C. deneoformans, C. neoformans and interspecies hybrids. Forty-four Cryptococcus spp. isolates were blindly identified using MALDI-TOF MS (Bruker Daltonics) and the expanded library. Their protein spectra were also submitted to hierarchical clustering and the resulting species were verified via Partial Least Squares Differential Analysis (PLS-DA) and Support-Vector Machine (SVM).ResultsMALDI-TOF MS coupled with the in-house library allowed 100% correct identification of C. deneoformans and C. neoformans but misidentified the interspecies hybrids. The same level of discrimination among C. deneoformans and C. neoformans was achieved applying SVM. The application of the PLS-DA and SVM algorithms in a two-step analysis allowed 96.95% and 96.55% correct discrimination of C. neoformans from the interspecies hybrids, respectively. Besides, PCA analysis prior to SVM provided 98.45% correct discrimination of the 3 species analysed in a one-step analysis.ConclusionsOur results indicate that MALDI-TOF MS could be a rapid and reliable tool for the correct discrimination of C. deneoformans and C. neoformans. The correct identification of the interspecies hybrids could only be achieved by hierarchical clustering with other protein spectra from the same species.

scholarly journals Application of MALDI-TOF MS for the Identification of Food Borne Bacteria

2013 ◽  
Vol 7 (1) ◽  
pp. 135-141 ◽  
Author(s):  
Melanie Pavlovic ◽  
Ingrid Huber ◽  
Regina Konrad ◽  
Ulrich Busch
Keyword(s):  
Associated Bacteria ◽  
Maldi Tof Ms ◽  
Maldi Tof ◽  
Flight Mass Spectrometry ◽  
Current State ◽  
Food Borne ◽  
Routine Identification ◽  
Identification Of Bacteria ◽  
Cost Efficient ◽  
Tof Ms

Matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS) has recently emerged as a powerful tool for the routine identification of clinical isolates. MALDI-TOF MS based identification of bacteria has been shown to be more rapid, accurate and cost-efficient than conventional phenotypic techniques or molecular methods. Rapid and reliable identification of food-associated bacteria is also of crucial importance for food processing and product quality. This review is concerned with the applicability of MALDI-TOF MS for routine identification of foodborne bacteria taking the specific requirements of food microbiological laboratories and the food industry into account. The current state of knowledge including recent findings and new approaches are discussed.

MALDI-TOF MS for rapid diagnosis of Anaerobiospirillum succiniciproducens, an unusual causative agent of bacteraemia in humans. Two case reports and literature review

Anaerobe ◽  
2019 ◽  
Vol 55 ◽  
pp. 130-135 ◽  
Author(s):  
Marina Alguacil-Guillen ◽  
Luis Ramos-Ruperto ◽  
Juan Carlos Ramos Ramos ◽  
Angel Robles-Marhuenda ◽  
Julio García-Rodriguez ◽  
...  
Keyword(s):  
Literature Review ◽  
Causative Agent ◽  
Case Reports ◽  
Rapid Diagnosis ◽  
Maldi Tof Ms ◽  
Anaerobiospirillum Succiniciproducens ◽  
Maldi Tof ◽  
Tof Ms

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 Evaluation of Vitek MS for Differentiation of Cryptococcus neoformans and Cryptococcus gattii Genotypes

2018 ◽  
Vol 57 (1) ◽  
Author(s):  
Lumena P. Machado Siqueira ◽  
Viviane M. Favero Gimenes ◽  
Roseli Santos de Freitas ◽  
Márcia de Souza Carvalho Melhem ◽  
Lucas Xavier Bonfietti ◽  
...  
Keyword(s):  
Cryptococcus Neoformans ◽  
Cryptococcus Gattii ◽  
Correct Identification ◽  
Content Type ◽  
Maldi Tof Ms ◽  
Mass Spectral ◽  
Maldi Tof ◽  
Flight Mass Spectrometry ◽  
Vitek Ms ◽  
Tof Ms

ABSTRACT Cryptococcus neoformans and Cryptococcus gattii are the main pathogenic species of invasive cryptococcosis among the Cryptococcus species. Taxonomic studies have shown that these two taxa have different genotypes or molecular types with biological and ecoepidemiological peculiarities. Matrix-assisted laser desorption ionization–time of flight mass spectrometry (MALDI-TOF MS) has been proposed as an alternative method for labor-intensive methods for C. neoformans and C. gattii genotype differentiation. However, Vitek MS, one of the commercial MALDI-TOF MS instruments, has not been yet been evaluated for this purpose. Thus, we constructed an in-house database with reference strains belonging to the different C. neoformans (VNI, VNII, VNIII, and VNIV) and C. gattii (VGI, VGII, VGIII, and VGIV) major molecular types by using the software Saramis Premium (bioMérieux, Marcy-l’Etoile, France). Then, this new database was evaluated for discrimination of the different genotypes. Our in-house database provided correct identification for all C. neoformans and C. gattii genotypes; however, due to the intergenotypic mass spectral similarities, a careful postanalytic evaluation is necessary to provide correct genotype identification.

Sign in / Sign up

Export Citation Format

Share Document