Improved Discrimination of Bacillus anthracis from Closely Related Species in the Bacillus cereus Sensu Lato Group Based on Matrix-Assisted Laser Desorption Ionization–Time of Flight Mass Spectrometry

Abstract

Discrimination of highly pathogenic bacteria, such as , from closely related species based on molecular biological methods is challenging. We applied matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS) to a collection of strains and close relatives in order to significantly improve the statistical confidence of identification results for this group of bacteria. Protein mass spectra of 189 verified and diverse strains of the group were generated using MALDI-TOF MS and subsequently analyzed with supervised and unsupervised statistical methods, such as shrinkage discriminant analysis (SDA) and principal-component analysis (PCA). We aimed at identifying specific biomarkers in the protein spectra of not present in closely related species. We could identify 7, 10, 18, and 14 -specific biomarker candidates that were absent in, ,, and strains, respectively. Main spectra (MSP) of a defined collection of strains were compiled using the Bruker Biotyper software and added to an in-house reference library. Reevaluation of this library with 15 hitherto untested strains of and yielded improved score values. The strains were identified with score values between 2.33 and 2.55 using the in-house database, while the same strains were identified with scores between 1.94 and 2.37 using the commercial database, and no false-positive identifications occurred using the in-house database.

The use of principle component analysis and MALDI-TOF MS for the differentiation of mineral forming Virgibacillus and Bacillus species isolated from sabkhas

“…[9][10][11][12] Moreover, it was shown that many microorganisms such as sulfur reducers, methanogens, phototrophs and heterotrophic aerobes have the ability to mediate dolomite formation. 13 In Dohat Faishakh sabkha, it was shown that bacteria, especially those belonging to the Virgibacillus genus were able to mediate mineralization process. 14 Indeed, in the reported works, the identication of these isolates was routinely performed by ribotyping; the 16s rRNA gene sequencing technique.…”

“…24 Expressed genes at a cultural condition could also be proled, leading to categorization of the corresponding strains. 13 MALDI-TOF-MS technique is rapid and reliable. 25 However, the identication of microorganisms is restricted to available protein proles in databases, which is not always the case.…”

The Gibberellin Producer Fusarium fujikuroi: Methods and Technologies in the Current Toolkit

“…The MALDI-TOF MS (Matrix-assisted laser desorption/ionization time-of-flight mass spectrometry) assay is an advanced tool for rapid and accurate identification of microorganisms. This technique has been widely applied to identify bacteria, yeasts and other fungi (Pinto et al, 2011;Mesureur et al, 2018;Pauker et al, 2018;Quero et al, 2019;Kim et al, 2019), especially for the identification of the human pathogens, whereas might be relatively less popular in the plant pathogen research at this moment. However, a broader application can be foresee in the near future based on its excellent accuracy and efficiency, and fast development of analyzing equipment.…”

Peptidome-Based Serotyping of The Food-Borne Pathogens Salmonella Enterica by Label-Free Mass Spectrometry

“…Mass spectrometry (MS) provides a high-throughput and relatively unbiased view of the protein profiling in bacteria [2], which facilitates differentiation of genetically-related bacteria and decoding the new nonsynonymous single-nucleotide polymorphisms. In recent years, a technique known as direct bacterial profiling, has increasingly been applied to dissect proteome for bacterial species identification via the matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS) [3][4][5][6][7][8][9][10]. A sufficient number of stable mass signals of major housekeeping proteins, such as ribosomal proteins, are reproducibly detected for bacterial species identification by using simple mass pattern-matching approaches or more sophisticated algorithms to compare and estimate the similarities between spectra [6,11,12,13,14,15,16,17,18].…”