The discriminatory power of MALDI-TOF mass spectrometry to differentiate between isogenic teicoplanin-susceptible and teicoplanin-resistant strains of methicillin-resistant<i>Staphylococcus aureus</i>

Majcherczyk, Paul; McKenna, T.; Moreillon, Philippe; Vaudaux, Pierre

doi:10.1111/j.1574-6968.2005.00060.x

Cited by 77 publications

(45 citation statements)

References 34 publications

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“…Finer discrimination is achieved by pulsed-field gel electrophoresis (PFGE) and spa typing (2). All of these methods need additional experimentation.In matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS), different spectra or signatures of cell extracts (3, 4, 5, 6) or whole cells (7,8,9,10,11,12) could be identified for different strains or groups of strains. An increasing number of laboratories use MALDI-TOF MS for the identification of S. aureus.…”

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confidence: 99%

Analysis of the Matrix-Assisted Laser Desorption Ionization–Time of Flight Mass Spectrum of Staphylococcus aureus Identifies Mutations That Allow Differentiation of the Main Clonal Lineages

et al. 2013

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Staphylococcus aureus causes a wide range of hospital infections. Often, these infections involve epidemic methicillin-resistant S. aureus (MRSA) strains that are transferred by health care workers to patients. In order to detect outbreaks that are caused by epidemic strains, the clinical isolates have to be typed. Multilocus sequence typing (MLST) relies on the sequence analysis of housekeeping genes and is used to allocate the strains to sequence types (ST), which can be grouped into clonal complexes (CC). This method has provided a detailed insight into the population structure of MRSA and methicillin-susceptible S. aureus (MSSA) strains (1). Finer discrimination is achieved by pulsed-field gel electrophoresis (PFGE) and spa typing (2). All of these methods need additional experimentation.In matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS), different spectra or signatures of cell extracts (3, 4, 5, 6) or whole cells (7,8,9,10,11,12) could be identified for different strains or groups of strains. An increasing number of laboratories use MALDI-TOF MS for the identification of S. aureus. However, the differences in the signatures of the strains have not been evaluated so far, because the discriminatory threshold of the software used in clinical settings is set up to assign the isolate to a species. To this end, more subtle differences are ignored. Another reason is that, so far, MALDI-TOF MS of whole bacterial cells has been employed in a heuristic manner, and for most species, the identities of the compounds that are detected in the measurements are unknown. Thus, the spectra are not well understood, and the variations in the signatures cannot be interpreted.In principle, two spectra might differ by signal intensity, loss of a signal, or by the shift of a signal. Variations in signal intensity are probably caused by expression differences, which might be directly correlated with culture conditions and, therefore, do not give unambiguous information about a genotype of the strain. The loss of a signal is caused by the total failure to express a protein or peptide, which in turn might indicate a mutation causing a frameshift or stop codon, but might also depend on culture conditions, mutations of regulatory factors, or sample preparation. Thus, there is no clear-cut correlation between the loss of a signal and a genotype. In contrast, peak shifts (i.e., loss of a signal coupled to the appearance of a new signal, both of which are correlated to the same peptide) correspond to point mutations in the genes of the peptides detected in the analysis; the mutation leads to an amino acid exchange that alters the molecular weight of the corresponding gene product.In order to characterize the clonal lineages of S. aureus in the MALDI-TOF MS, this work was aimed at the identification of the peptides that are detected in the spectra and that show mass variations between the clonal complexes of S. aureus. To this end, we analyzed the spectra of 401 S. aureus strains, concentrating on...

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Analysis of the Matrix-Assisted Laser Desorption Ionization–Time of Flight Mass Spectrum of Staphylococcus aureus Identifies Mutations That Allow Differentiation of the Main Clonal Lineages

et al. 2013

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“…5,18,[31][32][33][34][35][36][37][38] Moreover, MALDI-TOF MS has enabled the rapid detection of tick and mosquito vectors without requiring previous expertise in entomology. 39,40 Thus, this technique will be of use in the implementation of effective prevention measures for vector-borne diseases.…”

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The Ongoing Revolution of MALDI-TOF Mass Spectrometry for Microbiology Reaches Tropical Africa

Fall¹,

Lo²,

Samb-Ba³

et al. 2015

The American Society of Tropical Medicine and Hygiene

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Abstract. Matrix-assisted laser desorption ionization time-of-flight (MALDI-TOF) mass spectrometry (MS) represents a revolution in routine pathogen identification in clinical microbiology laboratories. A MALDI-TOF MS was introduced to tropical Africa in the clinical microbiology laboratory of the Hô pital Principal de Dakar (Senegal) and used for routine pathogen identification. Using MS, 2,429 bacteria and fungi isolated from patients were directly assayed, leading to the identification of 2,082 bacteria (85.7%) and 206 fungi (8.5%) at the species level, 109 bacteria (4.5%) at the genus level, and 16 bacteria (0.75%) at the family level. Sixteen isolates remained unidentified (0.75%). Escherichia coli was the most prevalent species (25.8%) followed by Klebsiella pneumoniae (14.8%), Streptococcus agalactiae (6.2%), Acinetobacter baumannii (6.1%), Pseudomonas aeruginosa (5.9%), and Staphylococcus aureus (5.9%). MALDI-TOF MS has also enabled the detection of rare bacteria and fungi. MALDI-TOF MS is a powerful tool for the identification of bacterial and fungal species involved in infectious diseases in tropical Africa.

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“…Zum einen wird versucht, die Technologie zur Bestimmung ausgew ä hlter Antibiotika-Resistenzen einzusetzen, wie etwa der Nachweis des Penicillin-bindenden Proteins PBP2a bei MRSA [37] [38,39] . Dabei wurde nicht der Nachweis des MRSA-typischen Penicillin-Bindungsprotein PBP2a gef ü hrt, sondern die Muster von Zellwandproteinen untersucht.…”

Section: Zuk ü Nftige Applikationen Der Maldi-tof Massenspektrometrieunclassified

Einsatz der Matrix-Assisted Laser Desorption/ionisation-Time of Flight Massenspektrometrie (MALDI-TOF MS) in der mikrobiologischen Routinediagnostik/Matrix-assisted laser desorption/ionisation time-of-flight mass spectrometry (MALDI-TOF MS) in clinical microbiological routine diagnostics

Schubert

2011

LaboratoriumsMedizin

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Zusammenfassung In der jüngsten Vergangenheit hat ein vollkommen neuartiger Ansatz zur Differenzierung von Bakterien und Pilzen die mikrobiologische Diagnostik erweitert: Die Identifikation von Keimen mittels MALDI-TOF Massenspektrometrie, die auf der Analyse ribosomaler Proteine beruht, ist bei vergleichbarer Validität der Untersuchungsergebnisse, wesentlich schneller als konventionelle, biochemische Differenzierungsverfahren. Neben der Identifizierung von Bakterienkolonien auf Festnährmedien können Bakterien und Sprosspilze aus positiven Blutkulturen oder direkt aus Urinproben analysiert werden. Derzeitige Weiterentwicklungen umfassen den Nachweis von β-Laktamase- und Carbapenemase-Aktivität der Bakterien sowie deren Genotypisierung unterhalb der Speziesebene.

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The discriminatory power of MALDI-TOF mass spectrometry to differentiate between isogenic teicoplanin-susceptible and teicoplanin-resistant strains of methicillin-resistantStaphylococcus aureus

Cited by 77 publications

References 34 publications

Analysis of the Matrix-Assisted Laser Desorption Ionization–Time of Flight Mass Spectrum of Staphylococcus aureus Identifies Mutations That Allow Differentiation of the Main Clonal Lineages

Analysis of the Matrix-Assisted Laser Desorption Ionization–Time of Flight Mass Spectrum of Staphylococcus aureus Identifies Mutations That Allow Differentiation of the Main Clonal Lineages

The Ongoing Revolution of MALDI-TOF Mass Spectrometry for Microbiology Reaches Tropical Africa

Einsatz der Matrix-Assisted Laser Desorption/ionisation-Time of Flight Massenspektrometrie (MALDI-TOF MS) in der mikrobiologischen Routinediagnostik/Matrix-assisted laser desorption/ionisation time-of-flight mass spectrometry (MALDI-TOF MS) in clinical microbiological routine diagnostics

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