scholarly journals MALDI-TOF MS as a method for rapid identification of Phytophthora de Bary, 1876

PeerJ ◽  
2021 ◽  
Vol 9 ◽  
pp. e11662
Author(s):  
Matěj Božik ◽  
Marcela Mrázková ◽  
Karolína Novotná ◽  
Markéta Hrabětová ◽  
Petr Maršik ◽  
...  

The number of described species of the oomycete genus Phytophthora is growing rapidly, highlighting the need for low-cost, rapid tools for species identification. Here, a collection of 24 Phytophthora species (42 samples) from natural as well as anthropogenic habitats were genetically identified using the internal transcribed spacer (ITS) and cytochrome c oxidase subunit I (COI) regions. Because genetic identification is time consuming, we have created a complementary method based on by matrix-assisted laser desorption ionization–time of flight mass spectrometry (MALDI-TOF MS). Both methods were compared and hypothesis that the MALDI-TOF MS method can be a fast and reliable method for the identification of oomycetes was confirmed. Over 3500 mass spectra were acquired, manually reviewed for quality control, and consolidated into a single reference library using the Bruker MALDI Biotyper platform. Finally, a database containing 144 main spectra (MSPs) was created and published in repository. The method presented in this study will facilitate the use of MALDI-TOF MS as a complement to existing approaches for fast, reliable identification of Phytophthora isolates.

2021 ◽  
Vol 12 ◽  
Author(s):  
Keyi Yu ◽  
Zhenzhou Huang ◽  
Ying Li ◽  
Qingbo Fu ◽  
Lirong Lin ◽  
...  

Shewanella species are widely distributed in the aquatic environment and aquatic organisms. They are opportunistic human pathogens with increasing clinical infections reported in recent years. However, there is a lack of a rapid and accurate method to identify Shewanella species. We evaluated here matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) for rapid identification of Shewanella. A peptide mass reference spectra (PMRS) database was constructed for the type strains of 36 Shewanella species. The main spectrum projection (MSP) cluster dendrogram showed that the type strains of Shewanella species can be effectively distinguished according to the different MS fingerprinting. The PMRS database was validated using 125 Shewanella test strains isolated from various sources and periods; 92.8% (n = 116) of the strains were correctly identified at the species level, compared with the results of multilocus sequence analysis (MLSA), which was previously shown to be a method for identifying Shewanella at the species level. The misidentified strains (n = 9) by MALDI-TOF MS involved five species of two groups, i.e., Shewanella algae–Shewanella chilikensis–Shewanella indica and Shewanella seohaensis–Shewanella xiamenensis. We then identified and defined species-specific biomarker peaks of the 36 species using the type strains and validated these selected biomarkers using 125 test strains. Our study demonstrated that MALDI-TOF MS was a reliable and powerful tool for the rapid identification of Shewanella strains at the species level.


2013 ◽  
Vol 2 (3) ◽  
pp. 104 ◽  
Author(s):  
Yuko Furukawa ◽  
Mitsuru Katase ◽  
Kazunobu Tsumura

Matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) has recently been demonstrated as a rapid and reliable method for identifying bacteria in colonies grown on culture plates. Rapid identification of food spoilage bacteria is important for ensuring the quality and safety of food. To shorten the time of analysis, several researchers have proposed the direct MALDI-TOF MS tequnics for identification of bacteria in clinical samples such as urine and positive blood cultures. In this study, processed soybean products (total 26 test samples) were initially conducted a culture enrichiment step and bacterial cells were separated from interfering components. Harvested bacterial cells were determined by MALDI-TOF MS and 16S rRNA gene sequencing method. Six processed soybean products (23%) were increased bacterial cells after culture enrichiment step and they were sucessfully obtained the accurate identification results by MALDI-TOF MS-based method without colony formation.


2021 ◽  
Vol 12 ◽  
Author(s):  
Chia-Ru Chung ◽  
Zhuo Wang ◽  
Jing-Mei Weng ◽  
Hsin-Yao Wang ◽  
Li-Ching Wu ◽  
...  

As antibiotics resistance on superbugs has risen, more and more studies have focused on developing rapid antibiotics susceptibility tests (AST). Meanwhile, identification of multiple antibiotics resistance on Staphylococcus aureus provides instant information which can assist clinicians in administrating the appropriate prescriptions. In recent years, matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS) has emerged as a powerful tool in clinical microbiology laboratories for the rapid identification of bacterial species. Yet, lack of study devoted on providing efficient methods to deal with the MS shifting problem, not to mention to providing tools incorporating the MALDI-TOF MS for the clinical use which deliver the instant administration of antibiotics to the clinicians. In this study, we developed a web tool, MDRSA, for the rapid identification of oxacillin-, clindamycin-, and erythromycin-resistant Staphylococcus aureus. Specifically, the kernel density estimation (KDE) was adopted to deal with the peak shifting problem, which is critical to analyze mass spectra data, and machine learning methods, including decision trees, random forests, and support vector machines, which were used to construct the classifiers to identify the antibiotic resistance. The areas under the receiver operating the characteristic curve attained 0.8 on the internal (10-fold cross validation) and external (independent testing) validation. The promising results can provide more confidence to apply these prediction models in the real world. Briefly, this study provides a web-based tool to provide rapid predictions for the resistance of antibiotics on Staphylococcus aureus based on the MALDI-TOF MS data. The web tool is available at: http://fdblab.csie.ncu.edu.tw/mdrsa/.


2018 ◽  
Vol 7 (4) ◽  
pp. 157-165
Author(s):  
Naïma L. Meghoufel ◽  
Abdelkader Homrani ◽  
Saïd Nemmiche ◽  
Nawel Benkrizi ◽  
Abdelkader E. Dahou ◽  
...  

In this paper, we investigated the lactic acid bacteria’s community of the Algerian goat’s Jben in order to define and preserve it. This cheese variety is only handmade with raw milk, and a dried flower of Cynara cardunculus is used instead of the animal rennet, it is also restricted in sub-Saharan prov-inces in Algeria, and no previous studies on its lactic acid bacteria composi-tion have been performed before. Matrix-assisted laser desorption ionization time of flight mass spectrometry (MALDI-TOF MS) procedure was used to identify 36 lactic acid bacteria isolated from artisanal Jben made from Arabia goat’s raw milk in Naâma (Algeria). The results showed the domination of the Enterococcus genus presents with four species: E. durans, E. faecalis, E. hirae and E. faecium. Lactococcus lactis and Leuconostoc mesenteroïdes were also detected. The species identified were favoured by the composition of goat’s raw milk microflora used and the artisanal manufacturing process of the cheese. The use of MALDI-TOF MS method provided us with a rapid diagnosis of the Jben lactic acid bacteria’s community. This method based on microbial abundant proteins fingerprint diagnosis was chosen for its fast, precise, low cost and less complicated analyse.


2009 ◽  
Vol 75 (21) ◽  
pp. 6745-6756 ◽  
Author(s):  
Tracy H. Hazen ◽  
Robert J. Martinez ◽  
Yanfeng Chen ◽  
Patricia C. Lafon ◽  
Nancy M. Garrett ◽  
...  

ABSTRACT Vibrio parahaemolyticus is a pathogenic marine bacterium that is the main causative agent of bacterial seafood-borne gastroenteritis in the United States. An increase in the frequency of V. parahaemolyticus-related infections during the last decade has been attributed to the emergence of an O3:K6 pandemic clone in 1995. The diversity of the O3:K6 pandemic clone and its serovariants has been examined using multiple molecular techniques including multilocus sequence analysis, pulsed-field gel electrophoresis, and group-specific PCR analysis. Matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS) has become a powerful tool for rapidly distinguishing between related bacterial species. In the current study, we demonstrate the development of a whole-cell MALDI-TOF MS method for the distinction of V. parahaemolyticus from other Vibrio spp. We identified 30 peaks that were present only in the spectra of the V. parahaemolyticus strains examined in this study that may be developed as MALDI-TOF MS biomarkers for identification of V. parahaemolyticus. We detected variation in the MALDI-TOF spectra of V. parahaemolyticus strains isolated from different geographical locations and at different times. The MALDI-TOF MS spectra of the V. parahaemolyticus strains examined were distinct from those of the other Vibrio species examined including the closely related V. alginolyticus, V. harveyi, and V. campbellii. The results of this study demonstrate the first use of whole-cell MALDI-TOF MS analysis for the rapid identification of V. parahaemolyticus.


2018 ◽  
Vol 30 (6) ◽  
pp. 813-820 ◽  
Author(s):  
Marta Pérez-Sancho ◽  
Ana I. Vela ◽  
Pilar Horcajo ◽  
María Ugarte-Ruiz ◽  
Lucas Domínguez ◽  
...  

Staphylococcus aureus encompasses 2 subspecies ( aureus and anaerobius) with significant differences in their epidemiology and pathogenicity. We evaluated the suitability of matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) for the rapid identification of both subspecies using a panel of 52 S. aureus isolates (30 subsp. anaerobius and 22 subsp. aureus) recovered from different origins, countries, and years. The on-board library identification system correctly identified 42 of 52 (81%) S. aureus isolates at the species level with score values >2.0. Limited performance was observed for differentiation of S. aureus subspecies (particularly subsp. anaerobius). Visual inspection of MALDI-TOF MS profiles identified 5 subspecies-specific mass peaks ( m/ z 3430 and 6861 in S. aureus subsp. anaerobius, and m/ z 4046, 6890, and 8093 in S. aureus subsp. aureus) with 100% sensitivity and specificity values, which is potentially useful for differentiating these subspecies. The suitability of 3 models, Genetic Analysis (GA), Quick Classifier (QC), and Supervised Neural Network, for automatic identification of both subspecies was evaluated using the Recognition Capability (RC) and Cross Validation (CV) values provided by the on-board ClinProTools software. The GA and QC models reached RC and CV values of 100%. Both models were externally validated using a panel of 26 S. aureus isolates of both subspecies, with both models correctly classifying all isolates of both subspecies. MALDI-TOF MS coupled with ClinProTools software represents a rapid and simple approach for S. aureus subspecies discrimination.


Author(s):  
Tiziana D’Inzeo ◽  
Barbara Fiori ◽  
Flora Marzia Liotti ◽  
Venere Cortazzo ◽  
Debora Talamonti ◽  
...  

Direct use of matrix-assisted laser desorption ionization–time of flight mass spectrometry (MALDI-TOF MS) on positive blood culture (PBC) bottles may accelerate the identification of bloodstream infection (BSI) causing organisms (1), particularly anaerobic bacteria for which BSI-associated mortality rates are high (2).…


2020 ◽  
Author(s):  
Patharapol Piamsomboon ◽  
Janthima Jaresitthikunchai ◽  
Tran Quang Hung ◽  
Sittiruk Roytrakul ◽  
Janenuj Wongtavatchai

Abstract Background: The majority of infectious diseases of cultured fish is caused by bacteria. Rapid identification of bacterial pathogens is necessary for immediate management. The present study developed a matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) for rapid identification of fish bacterial pathogens. Streptococcus agalactiae, Streptococcus iniae, Aeromonas hydrophila, Aeromonas veronii, and Edwardsiella tarda obtained from diseased fish were used as representative bacterial pathogens in this study. Bacterial peptides were extracted to create a Main Spectra Profile (MSP), and the MSPs of each bacterial species was added into the MALDI Biotyper database. Fifteen additional isolates of each bacterial species were tested to validate the utilized technique. Results: The MSPs of all field isolates were clearly distinguishable, and the MSPs of the same species were clustered together. However, the species identification when matched with the public MALDI Biotyper library (Bruker MALDI Biotyper) showed unreliable results. Accurate identification was only obtained when using the custom-made database, giving a 100% matching result with the reference method. Conclusion: This study demonstrates an alternative technique for effective identification of fish bacterial pathogens. Further applications require a broad, well-established database to accommodate prudent identification of many fish bacterial pathogens by MALDI-TOF MS.


2020 ◽  
Vol 58 (6) ◽  
Author(s):  
Jade Bokma ◽  
Laura Van Driessche ◽  
Piet Deprez ◽  
Freddy Haesebrouck ◽  
Marianne Vahl ◽  
...  

ABSTRACT Mycoplasma bovis is a leading cause of pneumonia in modern calf rearing. Fast identification is essential to ensure appropriate antimicrobial therapy. Therefore, the objective of this study was to develop a protocol to identify M. bovis from bronchoalveolar lavage fluid (BALf) with matrix-assisted laser desorption ionization–time of flight mass spectrometry MALDI-TOF MS and to determine the diagnostic accuracy in comparison with other techniques. BALf was obtained from 104 cattle, and the presence of M. bovis was determined in the following three ways: (i) rapid identification of M. bovis with MALDI-TOF MS (RIMM) (BALf was enriched and after 24, 48, and 72 h of incubation and was analyzed using MALDI-TOF MS), (ii) triplex real-time PCR for M. bovis, Mycoplasma bovirhinis, and Mycoplasma dispar, and (iii) 10-day incubation on selective-indicative agar. The diagnostic accuracy of the three tests was determined with Bayesian latent class modeling (BLCM). After 24 h of enrichment, M. bovis was identified with MALDI-TOF MS in 3 out of 104 BALf samples. After 48 and 72 h of enrichment, 32/104 and 38/100 samples, respectively, were M. bovis positive. Lipase-positive Mycoplasma-like colonies were seen in 28 of 104 samples. Real-time PCR resulted in 28/104 positive and 12/104 doubtful results for M. bovis. The BLCM showed a sensitivity (Se) and specificity (Sp) of 86.6% (95% credible interval [CI], 69.4% to 97.6%) and 86.4% (CI, 76.1 to 93.8) for RIMM. For real-time PCR, Se was 94.8% (CI, 89.9 to 97.9) and Sp was 88.9% (CI, 78.0 to 97.4). For selective-indicative agar, Se and Sp were 70.5% (CI, 52.1 to 87.1) and 93.9% (CI, 85.9 to 98.4), respectively. These results suggest that rapid identification of M. bovis with MALDI-TOF MS after an enrichment procedure is a promising test for routine diagnostics in veterinary laboratories.


2021 ◽  
Vol 3 (12) ◽  
Author(s):  
Richard D. Smith ◽  
Jerilyn R. Izac ◽  
Michael Ha ◽  
Hyojik Yang ◽  
J. Kristie Johnson ◽  
...  

Mobilized colistin resistance (mcr) genes confer resistance to colistin, a last-resort antibiotic for multidrug-resistant Gram-negative infections. In this case report, we describe a novel lipid-based matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) diagnostic used to rapidly identify an mcr-1-positive Escherichia coli directly from a patient with a urinary tract infection without the need for ex vivo growth.


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