title: Strategy for identification of Bacillus cereus and Bacillus thuringiensis strains closely related to Bacillus anthracis.
abstract: Bacillus cereus strains that are genetically closely related to B. anthracis can display anthrax-like virulence traits (A. R. Hoffmaster et al., Proc. Natl. Acad. Sci. USA 101:8449-8454, 2004). Hence, approaches that rapidly identify these "near neighbors" are of great interest for the study of B. anthracis virulence mechanisms, as well as to prevent the use of such strains for B. anthracis-based bioweapon development. Here, a strategy is proposed for the identification of near neighbors of B. anthracis based on single nucleotide polymorphisms (SNP) in the 16S-23S rRNA intergenic spacer (ITS) containing tRNA genes, characteristic of B. anthracis. By using restriction site insertion-PCR (RSI-PCR) the presence of two SNP typical of B. anthracis was screened in 126 B. cereus group strains of different origin. Two B. cereus strains and one B. thuringiensis strain showed RSI-PCR profiles identical to that of B. anthracis. The sequencing of the entire ITS containing tRNA genes revealed two of the strains to be identical to B. anthracis. The strict relationship with B. anthracis was confirmed by multilocus sequence typing (MLST) of four other independent loci: cerA, plcR, AC-390, and SG-749. The relationship to B. anthracis of the three strains described by MLST was comparable and even higher to that of four B. cereus strains associated with periodontitis in humans and previously reported as the closest known strains to B. anthracis. SNP in ITS containing tRNA genes combined with RSI-PCR provide a very efficient tool for the identification of strains closely related to B. anthracis.
authors.affiliation: Dipartimento di Scienze e Tecnologie Alimentari e Microbiologiche, Università degli Studi di Milano, via Celoria 2, 20133 Milan, Italy. daniele.daffonchio@unimi.it
authors.forename: Daniele
authors.initials: D
authors.lastname: Daffonchio
authors.forename: Noura
authors.initials: N
authors.lastname: Raddadi
authors.forename: Maya
authors.initials: M
authors.lastname: Merabishvili
authors.forename: Ameur
authors.initials: A
authors.lastname: Cherif
authors.forename: Lorenzo
authors.initials: L
authors.lastname: Carmagnola
authors.forename: Lorenzo
authors.initials: L
authors.lastname: Brusetti
authors.forename: Aurora
authors.initials: A
authors.lastname: Rizzi
authors.forename: Nina
authors.initials: N
authors.lastname: Chanishvili
authors.forename: Paolo
authors.initials: P
authors.lastname: Visca
authors.forename: Richard
authors.initials: R
authors.lastname: Sharp
authors.forename: Sara
authors.initials: S
authors.lastname: Borin
mesh_terms: D001408:Bacillus anthracis / Q000145:classification / Q000235:genetics* / Q000472:pathogenicity; D001409:Bacillus cereus / Q000145:classification / Q000235:genetics* / Q000472:pathogenicity; D001413:Bacillus thuringiensis / Q000145:classification / Q000235:genetics* / Q000472:pathogenicity; D004269:DNA, Bacterial / Q000235:genetics; D021903:DNA, Ribosomal Spacer / Q000235:genetics; D005798:Genes, Bacterial; D006801:Humans; D007438:Introns; D008969:Molecular Sequence Data; D010518:Periodontitis / Q000382:microbiology; D010802:Phylogeny; D016133:Polymerase Chain Reaction; D020641:Polymorphism, Single Nucleotide; D012329:RNA, Bacterial / Q000235:genetics; D012336:RNA, Ribosomal, 16S / Q000235:genetics; D012338:RNA, Ribosomal, 23S / Q000235:genetics; D013045:Species Specificity
chemical_list: D004269:DNA, Bacterial; D021903:DNA, Ribosomal Spacer; D012329:RNA, Bacterial; D012336:RNA, Ribosomal, 16S; D012338:RNA, Ribosomal, 23S