MALDI-TOF Mass Spectroscopy Applications in Clinical Microbiology

There is a range of proteomics methods to spot and analyze bacterial protein contents such as liquid chromatography-mass spectrometry (LC-MS), two-dimensional gel electrophoresis, and matrix-assisted laser desorption/ionization mass spectrometry (MALDI-TOF MS), which give comprehensive information about the microorganisms that may be helpful within the diagnosis and coverings of infections. Microorganism identification by mass spectrometry is predicted on identifying a characteristic spectrum of every species so matched with an outsized database within the instrument. MALDI-TOF MS is one of the diagnostic methods, which is a straightforward, quick, and precise technique, and is employed in microbial diagnostic laboratories these days and may replace other diagnostic methods. This method identifies various microorganisms such as bacteria, fungi, parasites, and viruses, which supply comprehensive information. One of the MALDI-TOF MS’s crucial applications is bacteriology, which helps identify bacterial species, identify toxins, and study bacterial antibiotic resistance. By knowing these cases, we will act more effectively against bacterial infections.

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Rapid identification of Legionella species by mass spectrometry

Journal of Medical Microbiology ◽

10.1099/jmm.0.014100-0 ◽

2010 ◽

Vol 59 (3) ◽

pp. 273-284 ◽

Cited By ~ 42

Author(s):

Claire Moliner ◽

Christophe Ginevra ◽

Sophie Jarraud ◽

Christophe Flaudrops ◽

Marielle Bedotto ◽

...

Keyword(s):

Mass Spectrometry ◽

Bacterial Species ◽

Rapid Identification ◽

Species Level ◽

Blind Test ◽

Maldi Tof Ms ◽

Maldi Tof ◽

Tract Infections ◽

Pcr Targeting ◽

Tof Ms

Legionella species are facultative, intracellular bacteria that infect macrophages and protozoa, with the latter acting as transmission vectors to humans. These fastidious bacteria mostly cause pulmonary tract infections and are routinely identified by various molecular methods, mainly PCR targeting the mip gene and sequencing, which are expensive and time-consuming. Recently, matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF-MS) has emerged as a rapid and inexpensive method for identification of bacterial species. This study evaluated the use of MALDI-TOF-MS for rapid species and serogroup identification of 21 Legionella species recognized as human pathogens. To this end, a reference MS database was developed including 59 Legionella type strains, and a blind test was performed using 237 strains from various species. Two hundred and twenty-three of the 237 strains (94.1 %) were correctly identified at the species level, although ten (4.2 %) were identified with a score lower than 2.0. Fourteen strains (5.9 %) from eight species were misidentified at the species level, including seven (3.0 %) with a significant score, suggesting an intraspecific variability of protein profiles within some species. MALDI-TOF-MS was reproducible but could not identify Legionella strains at the serogroup level. When compared with mip gene sequencing, MALDI-TOF-MS exhibited a sensitivity of 99.2 and 89.9 % for the identification of Legionella strains at the genus and species level, respectively. This study demonstrated that MALDI-TOF-MS is a reliable tool for the rapid identification of Legionella strains at the species level.

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Rapid and cost-effective identification of Bartonella species using mass spectrometry

Journal of Medical Microbiology ◽

10.1099/jmm.0.009647-0 ◽

2009 ◽

Vol 58 (9) ◽

pp. 1154-1159 ◽

Cited By ~ 43

Author(s):

Pierre-Edouard Fournier ◽

Carine Couderc ◽

Sylvain Buffet ◽

Christophe Flaudrops ◽

Didier Raoult

Keyword(s):

Mass Spectrometry ◽

Species Identification ◽

Chemical Reactivity ◽

Bacterial Species ◽

Cost Effective ◽

Molecular Techniques ◽

Maldi Tof Ms ◽

Maldi Tof ◽

Flight Mass Spectrometry ◽

Tof Ms

Bacteria of the genus Bartonella are emerging zoonotic bacteria recognized in a variety of human diseases. Due to their poor chemical reactivity, these fastidious bacteria are poorly characterized using routine phenotypic laboratory tests. Identification is usually achieved using molecular techniques that are time-consuming, expensive and technically demanding. Recently, matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) has emerged as a new technique for bacterial species identification. This study evaluated the use of MALDI-TOF MS for rapid genus and species identification of Bartonella species. Reference strains representing 17 recognized Bartonella species were studied. For each species, MS spectra for four colonies were analysed. The consensus spectrum obtained for each species was unique among spectra obtained for 2843 bacteria within the Bruker database, including 109 alphaproteobacteria. Thirty-nine additional blind-coded Bartonella strains were correctly identified at the species level, including 36 with a significant score. Altogether, these data demonstrate that MS is an accurate and reproducible tool for rapid and inexpensive identification of Bartonella species.

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Monitoring the size and the stability of zinc oxide quantum dots in biological media: a soft ionization mass spectrometry technique (MALDI-TOF-MS)

MRS Proceedings ◽

10.1557/opl.2015.620 ◽

2015 ◽

Vol 1793 ◽

pp. 7-12

Author(s):

Jean-Jacques Gaumet ◽

Gabriel Gaiffe ◽

Clément Dezanet ◽

Stéphane Dalmasso ◽

Pierre Magri ◽

...

Keyword(s):

Mass Spectrometry ◽

Quantum Dots ◽

Sol Gel ◽

Ionization Mass ◽

Maldi Tof Ms ◽

Maldi Tof ◽

Physico Chemical ◽

The Stability ◽

Zno Qds ◽

Tof Ms

ABSTRACTWe present herein a joint physical/physico-chemical study and, more specifically, the first application of Matrix Assisted Laser Desorption Ionization coupled with Time of Flight Mass Spectrometry (MALDI-TOF-MS) to analyze small-sized ZnO quantum dots (QDs) (2.8-3.1 nm diameter range) synthesized by sol-gel chemistry and stabilized through an aminosilane coating. A careful investigation of the stability of ZnO QDs was initiated once these dots were dispersed in different media (water, biological buffer) for a period up to 3 weeks. Positive ion mode mass spectra MALDI-TOF-MS combined with optical spectrometry was used to monitor the stability of ZnO QDs when aging. Such a unique combination of MALDI-TOF-MS and physico-chemical techniques is likely to bring new insights into the structure analysis, the stability and consequently the potential toxicity of QDs.

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Effect of Culture Conditions on Microorganism Identification by Matrix-Assisted Laser Desorption Ionization Mass Spectrometry

Applied and Environmental Microbiology ◽

10.1128/aem.71.1.58-64.2005 ◽

2005 ◽

Vol 71 (1) ◽

pp. 58-64 ◽

Cited By ~ 167

Author(s):

Nancy Valentine ◽

Sharon Wunschel ◽

David Wunschel ◽

Catherine Petersen ◽

Karen Wahl

Keyword(s):

Mass Spectrometry ◽

Laser Desorption ◽

Ionization Mass ◽

Laser Desorption Ionization ◽

Maldi Tof Ms ◽

Desorption Ionization ◽

Maldi Tof ◽

Tof Ms ◽

Matrix Assisted Laser ◽

Matrix Assisted Laser Desorption

ABSTRACT Matrix-assisted laser desorption ionization-time-of-flight mass spectrometry (MALDI-TOF MS) has been used to identify bacteria based upon protein signatures. This research shows that while some different proteins are produced by vegetative bacteria when they are cultured in different growth media, positive identification with MALDI-TOF MS is still possible with the protocol established at the Pacific Northwest National Laboratory (K. H. Jarman, S. T. Cebula, A. J. Saenz, C. E. Petersen, N. B. Valentine, M. T. Kingsley, and K. L. Wahl, Anal. Chem. 72:1217-1223, 2000). A core set of small proteins remain constant under at least four different culture media conditions and blood agar plates, including minimal medium M9, rich media, tryptic soy broth (TSB) or Luria-Bertani (LB) broth, and blood agar plates, such that analysis of the intact cells by matrix-assisted laser desorption/ionization mass spectrometry allows for consistent identification.

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Using MALDI-TOF mass spectrometry to identify ticks collected on domestic and wild animals from the Democratic Republic of the Congo

Experimental and Applied Acarology ◽

10.1007/s10493-021-00629-z ◽

2021 ◽

Author(s):

Steve Ngoy ◽

Adama Zan Diarra ◽

Anne Laudisoit ◽

Guy-Crispin Gembu ◽

Erik Verheyen ◽

...

Keyword(s):

Mass Spectrometry ◽

Democratic Republic ◽

Morphological Identification ◽

Ionization Mass ◽

Wild Animals ◽

Maldi Tof Ms ◽

Maldi Tof ◽

Republic Of The Congo ◽

Reference Specimens ◽

Tof Ms

AbstractMatrix-assisted laser desorption/ionization mass spectrometry (MALDI-TOF MS) has recently emerged as an alternative to morphological and molecular tools to identify tick species. In this study, we set out to evaluate and confirm the ability of MALDI-TOF MS to identify different species of ticks collected in the Democratic Republic of the Congo and preserved in 70% ethanol. A total of 575 ticks, of which 530 were collected from domestic pigs and 45 from wild animals, were subjected to MALDI-TOF MS analysis to evaluate the intraspecies reproducibility and interspecies specificity of MS profiles obtained from the different species. Morphologically, the ticks belonged to seven different species, namely Rhipicephalus complanatus, Rhipicephalus congolensis, Haemaphysalis muhsamae, Ixodes cumulatimpunctatus, Amblyomma exornatum, Amblyomma compressum and an unidentified Rhipicephalus sp. A total of 535/575 (93%) of the spectra obtained were of good enough quality to be used for our analyses. Our home-made MALDI-TOF MS arthropod database was upgraded with spectra obtained from between one and five randomly selected specimens per species. For these reference specimens, molecular identification of the ticks was also made using 16S, 12S rDNA genes and the Cox1 mtDNA gene sequencing. The remaining good quality spectra were then queried against the upgraded MALDI-TOF MS database, showing that 100% were in agreement with the morphological identification, with logarithmic score values (LSVs) between 1.813 and 2.51. The consistency between our morphological, molecular and MALDI-TOF MS identification confirms the capability and precision of MALDI-TOF MS for tick identification.

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Rapid identification of Nocardia cyriacigeorgica from a brain abscess patient using MALDI-TOF-MS

Oxford Medical Case Reports ◽

10.1093/omcr/omaa088 ◽

2020 ◽

Vol 2020 (10) ◽

Author(s):

Mohammed AlMogbel ◽

Mohammed AlBolbol ◽

Noura Elkhizzi ◽

Hisham AlAjlan ◽

John Philip Hays ◽

...

Keyword(s):

Mass Spectrometry ◽

Bacterial Species ◽

Rapid Identification ◽

Clinical Samples ◽

Maldi Tof Ms ◽

Maldi Tof ◽

Flight Mass Spectrometry ◽

Nocardia Cyriacigeorgica ◽

Diagnostic Microbiology ◽

Tof Ms

Abstract Nocardia cyriacigeorgica (N. cyriacigeorgica) is most frequently associated with human infections, including chronic bronchitis, pulmonary disease and brain abscesses. In general, N. cyriacigeorgica causes infections in immunocompromised individuals and has been reported in clinical samples worldwide. However, the isolation and speciation of N. cyriacigeorgica in the routine diagnostic microbiology laboratory are complicated and time consuming. Recent mass spectrometry techniques such as matrix-assisted laser desorption/ionization time-of-flight-mass spectrometry (MALDI-TOF-MS) have been successfully integrated into many routine diagnostic microbiology laboratories, allowing for the rapid, accurate and simple identification and speciation of many different microorganisms, including difficult-to-identify bacterial species. Here, we present a case report of a 65-year-old female patient from the neurology ward of Prince Sultan Military Medical City in Riyadh, Saudi Arabia, who was infected with N. cyriacigeorgica. The bacterium was successfully identified by MALDI-TOF-MS, with species identification subsequently confirmed by sequence analysis of the 16S ribosomal RNA.

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Diagnostic accuracy of MALDI-TOF mass spectrometry for the direct identification of clinical pathogens from urine

Open Medicine ◽

10.1515/med-2020-0038 ◽

2020 ◽

Vol 15 (1) ◽

pp. 266-273

Author(s):

Min Tang ◽

Jia Yang ◽

Ying Li ◽

Luhua Zhang ◽

Ying Peng ◽

...

Keyword(s):

Mass Spectrometry ◽

Likelihood Ratio ◽

Meta Analysis ◽

Positive Likelihood Ratio ◽

Negative Likelihood Ratio ◽

Urine Samples ◽

Direct Identification ◽

Maldi Tof Ms ◽

Maldi Tof ◽

Tof Ms

AbstractMatrix-assisted laser desorption ionization time of flight mass spectrometry (MALDI-TOF MS) has become one of the most popular methods for the rapid and cost-effective detection of clinical pathogenic microorganisms. This study aimed to evaluate and compare the diagnostic performance of MALDI-TOF MS with that of conventional approaches for the direct identification of pathogens from urine samples. A systematic review was conducted based on a literature search of relevant databases. The pooled sensitivity, specificity, positive likelihood ratio (PLR), negative likelihood ratio (NLR) and area under the summary receiver operating characteristic (SROC) curve of the combined studies were estimated. Nine studies with a total of 3920 subjects were considered eligible and included in the meta-analysis. The pooled sensitivity was 0.85 (95% CI 0.79-0.90), and the pooled specificity was 0.93 (95% CI 0.82-0.97). The PLR and NLR were 11.51 (95% CI 4.53-29.26) and 0.16 (95% CI 0.11-0.24), respectively. The area under the SROC curve was 0.93 (95% CI 0.91-0.95). Sensitivity analysis showed that the results of this meta-analysis were stable. MALDI-TOF MS could directly identify microorganisms from urine samples with high sensitivity and specificity.

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The Use of MALDI-TOF Mass Spectrometry to Analyze Commensal Oral Yeasts in Nursing Home Residents

Microorganisms ◽

10.3390/microorganisms9010142 ◽

2021 ◽

Vol 9 (1) ◽

pp. 142

Author(s):

Jang-Jih Lu ◽

Hsiu-Jung Lo ◽

Chih-Hua Lee ◽

Mei-Jun Chen ◽

Chih-Chao Lin ◽

...

Keyword(s):

Mass Spectrometry ◽

Nursing Home ◽

Dna Sequences ◽

Nursing Home Residents ◽

Practical Method ◽

Elderly Subjects ◽

Maldi Tof Ms ◽

Maldi Tof ◽

Oral Yeasts ◽

Tof Ms

Matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF MS) is a rapid and accurate method to identify microorganisms in clinical laboratories. This study isolates yeast-like microorganisms in the oral washes that are collected from non-bedridden nursing home residents, using CHROMagar Candida plates, and identifies them using Bruker MALDI-TOF MS. The ribosomal DNA sequences of the isolates are then examined. Three hundred and twenty yeast isolates are isolated from the oral washes. Candida species form the majority (78.1%), followed by Trichosporon/Cutaneotrichosporon species (8.8%). Bruker MALDI-TOF MS gives a high-level confidence, with a log(score) value of ≥1.8, and identifies 96.9% of the isolates. There are six inconclusive results (1.9%), and those sequences are verified as rare clinical species, including Candida ethanolica, Cutaneotrichosporon jirovecii, Exophiala dermatitidis, and Fereydounia khargensis. Almost all of the isolates have a regular color on the CHROMagar Candida plates. If the colonies are grouped by color on the plates, a specific dominant yeast species is present in each color group, except for purple or orange isolates. In conclusion, MALDI-TOF MS is verified as a fast, accurate and practical method to analyze oral yeasts in elderly subjects.

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Microorganism idenitfication – stability and correctness of mass spectrometry method (MALDI TOF MS)

Diagnostyka Laboratoryjna ◽

10.5604/01.3001.0015.0264 ◽

2021 ◽

Vol 56 (4) ◽

pp. 1-12

Author(s):

Łukasz Hildebrant ◽

Urszula Wendt

Keyword(s):

Mass Spectrometry ◽

Quality Control ◽

Control System ◽

High Stability ◽

Spectrometry Method ◽

Maldi Tof Ms ◽

Mass Spectrometry Method ◽

Maldi Tof ◽

Reference Strains ◽

Tof Ms

Introduction: MALDI TOF MS method is increasingly used in routine microbiological diagnostics to identify clinical strains. The result of the identification test is based on the measurement of the mass, charge and flight time of the protein ions. This makes it possible to monitor and supervise the method using a numerical score developed with statistical techniques. Aim: The study aimed to determine the stability and correctness of the mass spectrometry method. Materials and methods: To evaluate the characteristics of the method, microbial identification tests were performed using reference strains. All tests were performed as part of the MALDI TOF MS internal quality control system. Results: All reference strains (100%) were correctly identified to the species level, although the score values were not always within the reliability criteria of the results established by the producer. It was found that the mean values of the score were from 2.000 – 2.299 (49.2%) and 2.300 – 3.000 (50.0%). The coefficient of variation for control tests performed in the consecutive years ranged from 5.18 – 6.56%, which evidence of the high stability of the method. For individual species, reproducibility precision over the 8 years ranged from 2.89% (n = 13) for Enterococcus faecalis ATCC 51299 to 7.02% (n = 28) for Klebsiella pneumoniae ATCC 700603, which proves the high precision of measurements. Conclusions: The mass spectrometry method is characterized by very high stability and correctness. The intra-laboratory quality control system using reference strains is a useful tool for monitoring and supervising the method and laboratory personnel competency performing identification tests during routine microbiological work.

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MALDI-TOF-MS Assay to Detect the Hemizygous 22q11.2 Deletion in DNA from Dried Blood Spots

Clinical Chemistry ◽

10.1373/clinchem.2015.247148 ◽

2016 ◽

Vol 62 (1) ◽

pp. 287-292 ◽

Cited By ~ 3

Author(s):

Lisa J Kobrynski ◽

Golriz K Yazdanpanah ◽

Deborah Koontz ◽

Francis K Lee ◽

Robert F Vogt

Keyword(s):

Dried Blood Spots ◽

Diagnostic Methods ◽

Deletion Syndrome ◽

Congenital Defects ◽

22Q11.2 Deletion ◽

Maldi Tof Ms ◽

Blood Spots ◽

Maldi Tof ◽

Hemizygous Deletion ◽

Tof Ms

Abstract BACKGROUND A hemizygous deletion of 1.5–3 Mb in 22q11.2 causes a distinct clinical syndrome with variable congenital defects. Current diagnostic methods use fluorescent in situ hybridization (FISH) or comparative genomic hybridization by microarray to detect the deletion. Neither method is suitable for newborn screening (NBS), since they cannot be performed on dried blood spots (DBS). We developed a MALDI-TOF-MS assay that uses DBS to measure the hemizygous deletion of UFD1L, located within the 22q11.2 region. METHODS We used DBS from 54 affected patients, previously tested by FISH or microarray, and 100 cord blood samples to evaluate the performance of the MALDI-TOF-MS assay. With a single primer pair, a 97-base oligonucleotide within UFD1L was amplified, as was a sequence on chromosome 18 that differs by 2 nucleotides. A multiplexed, single-base extension reaction created allele-specific products for MALDI-TOF-MS detection. The products were spotted onto a silicon chip, and the height of the spectral peaks identified the relative amounts of target and reference gene. RESULTS The median ratio of the spectral peak for each UFD1L target:reference base was 0.96 and 0.99 for controls, compared with 0.35 and 0.53 for 22q11 deletion syndrome patients. There was 100% concordance between FISH/microarray and MALDI-TOF-MS in all patients with 22q11.2 deletion syndrome. CONCLUSIONS This method can be reliably performed with DBS and is suitable for high sample throughput. This assay may be considered for use in population-based NBS for 22q11.2 deletion.

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