title: MALDI-TOF MS portrait of emetic and non-emetic Bacillus cereus group members.
abstract: The number of foodborne intoxications caused by emetic Bacillus cereus isolates has increased significantly. As such, rapid and reliable methods to identify emetic strains appear to be clinically relevant. In this study, intact cell matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) was used to differentiate emetic and non-emetic bacilli. The phyloproteomic clustering of 34 B. cereus emetic and 88 non-emetic isolates classified as B. cereus, Bacillus thuringiensis, Bacillus weihenstephanensis, and Bacillus mycoides, showed (i) a clear separation of both groups at a similarity level of 43%, and (ii) a high relatedness among the emetic isolates (similarity of 78%). Specifically, 83 mass peak classes were recognized in the spectral window range between m/z 4000 and 12 000 that were tentatively assigned to 41 protein variants based on a bioinformatic approach. Mass variation between the emetic and the non-emetic subsets was recorded for 27 of them, including ten ribosomal subunit proteins, for which inter-strain polymorphism was confirmed by gene sequencing. Additional peaks were assigned to other proteins such as small acid soluble proteins, cold shock proteins and hypothetical proteins, e.g., carbohydrate kinase. Moreover, the results were supported by in silico analysis of the biomarkers in 259 members of B. cereus group, including Bacillus anthracis, based on their whole-genome sequences. In conclusion, the proteomic profiling by MALDI-TOF MS is a promising and rapid method for pre-screening B. cereus to identify medically relevant isolates and for epidemiologic purposes.
authors.affiliation: Department of Microbiology, Medical University of Bialystok, Bialystok, Poland.
authors.forename: Krzysztof
authors.initials: K
authors.lastname: Fiedoruk
authors.affiliation: Department of Microbiology, Medical University of Bialystok, Bialystok, Poland.
authors.forename: Tamara
authors.initials: T
authors.lastname: Daniluk
authors.affiliation: Department of Microbiology, University of Bialystok, Bialystok, Poland.
authors.forename: Angelika
authors.initials: A
authors.lastname: Fiodor
authors.affiliation: Department of Microbiology, University of Bialystok, Bialystok, Poland.
authors.forename: Ewa
authors.initials: E
authors.lastname: Drewicka
authors.affiliation: Department of Microbiology, University of Bialystok, Bialystok, Poland.
authors.forename: Katarzyna
authors.initials: K
authors.lastname: Buczynska
authors.affiliation: Department of Microbiology, Medical University of Bialystok, Bialystok, Poland.
authors.forename: Katarzyna
authors.initials: K
authors.lastname: Leszczynska
authors.affiliation: Department of Natural and Mathematical Science, California Baptist University, Riverside, USA.|Department of Entomology, University of California, Riverside, USA.
authors.forename: Dennis Ken
authors.initials: DK
authors.lastname: Bideshi
authors.affiliation: Department of Microbiology, University of Bialystok, Bialystok, Poland.|Laboratory of Applied Microbiology, University of Bialystok, Bialystok, Poland.
authors.forename: Izabela
authors.initials: I
authors.lastname: Swiecicka
mesh_terms: D001407:Bacillus / Q000302:isolation & purification; D001409:Bacillus cereus / Q000302:isolation & purification*; D001426:Bacterial Proteins / Q000737:chemistry / Q000235:genetics; D015373:Bacterial Typing Techniques / Q000379:methods*; D004639:Emetics / Q000302:isolation & purification*; D011110:Polymorphism, Genetic; D040901:Proteomics / Q000379:methods; D017422:Sequence Analysis, DNA; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization / Q000379:methods*
chemical_list: D001426:Bacterial Proteins; D004639:Emetics
keywords: Bacillus cereus sensu lato; Discriminative proteins; Emetic isolates; MALDI-TOF MS; Phylogeny