Application of matrix‐assisted laser desorption/ionization time‐of‐flight mass spectrometry for the study of Helicobacter pylori

Abstract

The characteristics of matrix-assisted laser desorption/ionization time-of-flight (MALDI-TOF) mass spectrometry based investigation of extremely variable bacteria such as Helicobacter pylori were studied. H. pylori possesses a very high natural variability. Accurate tools for species identification and epidemiological characterization could help the scientific community to better understand the transmission pathways and virulence mechanisms of these bacteria. Seventeen clinical as well as two laboratory strains of H. pylori were analyzed by the MALDI Biotyper method for rapid species identification. Mass spectra collected were found containing 7-13 significant peaks per sample, and only six protein signals were identical for more than half of the strains. Four of them could be assigned to ribosomal proteins RL32, RL33, RL34, and RL36. The reproducible peak with m/z 6948 was identified as a histidine-rich metal-binding polypeptide by tandem mass spectrometry (MS/MS). In spite of the evident protein heterogeneity of H. pylori the mass spectra collected for a particular strain under several cultivations were highly reproducible. Moreover, all clinical strains were perfectly identified as H. pylori species through comparative analysis using the MALDI Biotyper software (Bruker Daltonics, Germany) by pattern matching against a database containing mass spectra from different microbial strains (n = 3287) including H. pylori 26695 and J99. The results of this study allow the conclusion that the MALDI-TOF direct bacterial profiling is suited for H. pylori identification and could be supported by mass spectra fragmentation of the observed polypeptide if necessary.

Phenotypical and Mass Spectral Assessment Methods for Identification of Some Contagious Mastitis Pathogens

“…agalactiae and 72% of CNS were identified by API system. The results tabulated in the current study, supported by similar and widespread data for clinical human and veterinary microbiology (Ilina et al, 2009;Lartigue et al, 2009; Science Publications Marklein et al, 2009;Nagy et al, 2009;Barreiro et al, 2010;Dubois et al, 2010;Ilina et al, 2010;Seibold et al, 2010;Moon et al, 2013;Raemy et al, 2013), confirmed that MALDI-TOF MS contributes in the fast identification of bacteria (one day versus five to eight days for conventional identification) and consequently the chance of an earlier treatment of subclinical and clinical mastitis with suitable antimicrobial agents will be carried out. In addition, in the dairy industry, MALDITOF MS can provides a faster, cheaper and more reliable identification of microorganisms isolated from milk of animals witth clinical and subclinical mastitis.…”

Matrix-Assisted Laser Desorption Ionization–Time of Flight Mass Spectrometry: a Fundamental Shift in the Routine Practice of Clinical Microbiology

“…These studies were expanded in a 2010 publication examining the application of MALDI-TOF MS for the species-specific identification of H. pylori (235). Using a collection of 2 reference strains and 17 clinical isolates, MALDI-TOF MS analysis was performed with the Bruker BioTyper 2.0 software.…”

“…Despite significant differences observed in MALDI spectra analyzed both in this study and previously, the BioTyper database identified all isolates tested as H. pylori. Thus, MALDI-TOF MS was deemed suitable for the identification of H. pylori, even in the case of an organism which exhibits high levels of genetic plasticity (234,235).…”

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

“…Anders als bei den biochemischen Testsystemen handelt es sich beim MALDI-TOF MS-System um ein offenes, bei dem die Datenbank auch vom Anwender eigenst ä ndig erweitert werden kann. Durch entsprechende Erg ä nzungen der Referenz-Spektren der Datenbanken konnte eine nahezu 100 % Identifi zierungsrate von Neisserien [11] , Clostridien [12] , Mycobakterien [13] , Salmonellen [14] , vergr ü nenden Streptokokken [15] und Helicobacter pylori [16] erreicht werden. W ä hrend das MALDI-TOF MS-System im Vergleich zu biochemischen Testsystemen im Bereich der Differenzierung von Enterobakterien, Staphylokokken und Streptokokken vergleichbar gute Ergebnisse liefert, zeigt es deutliche Vorteile bei der Differenzierung von Gram-positiven St ä bchen [17] , Anaerobiern und einigen Nonfermentern [18,19] .…”