Intraclade variability in toxin production and cytotoxicity of Bacillus cereus group type strains and dairy-associated isolates

Rachel A. Miller, Jiahui Jian, Sarah M. Beno, Martin Wiedmann, Jasna Kovac

Research output: Contribution to journalArticle

13 Citations (Scopus)

Abstract

While some species in the Bacillus cereus group are well-characterized human pathogens (e.g., B. anthracis and B. cereus sensu stricto), the pathogenicity of other species (e.g., B. pseudomycoides) either has not been characterized or is presently not well understood. To provide an updated characterization of the pathogenic potential of species in the B. cereus group, we classified a set of 52 isolates, including 8 type strains and 44 isolates from dairy-associated sources, into 7 phylogenetic clades and characterized them for (i) the presence of toxin genes, (ii) phenotypic characteristics used for identification, and (iii) cytotoxicity to human epithelial cells. Overall, we found that B. cereus toxin genes are broadly distributed but are not consistently present within individual species and/or clades. After growth at 37°C, isolates within a clade did not typically show a consistent cytotoxicity phenotype, except for isolates in clade VI (B. weihenstephanensis/B. mycoides), where none of the isolates were cytotoxic, and isolates in clade I (B. pseudomycoides), which consistently displayed cytotoxic activity. Importantly, our study highlights that B. pseudomycoides is cytotoxic toward human cells. Our results indicate that the detection of toxin genes does not provide a reliable approach to predict the pathogenic potential of B. cereus group isolates, as the presence of toxin genes is not always consistent with cytotoxicity phenotype. Overall, our results suggest that isolates from multiple B. cereus group clades have the potential to cause foodborne illness, although cytotoxicity is not always consistently found among isolates within each clade.

Original languageEnglish (US)
Article numbere02479-17
JournalApplied and environmental microbiology
Volume84
Issue number6
DOIs
StatePublished - Mar 1 2018

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Bacillus cereus
toxin
cytotoxicity
dairies
toxins
gene
phenotype
pathogenicity
Genes
genes
Phenotype
Bacillus anthracis
Foodborne Diseases
pathogen
foodborne illness
phylogenetics
Virulence
epithelial cells
Epithelial Cells
pathogens

All Science Journal Classification (ASJC) codes

  • Biotechnology
  • Food Science
  • Applied Microbiology and Biotechnology
  • Ecology

Cite this

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title = "Intraclade variability in toxin production and cytotoxicity of Bacillus cereus group type strains and dairy-associated isolates",
abstract = "While some species in the Bacillus cereus group are well-characterized human pathogens (e.g., B. anthracis and B. cereus sensu stricto), the pathogenicity of other species (e.g., B. pseudomycoides) either has not been characterized or is presently not well understood. To provide an updated characterization of the pathogenic potential of species in the B. cereus group, we classified a set of 52 isolates, including 8 type strains and 44 isolates from dairy-associated sources, into 7 phylogenetic clades and characterized them for (i) the presence of toxin genes, (ii) phenotypic characteristics used for identification, and (iii) cytotoxicity to human epithelial cells. Overall, we found that B. cereus toxin genes are broadly distributed but are not consistently present within individual species and/or clades. After growth at 37°C, isolates within a clade did not typically show a consistent cytotoxicity phenotype, except for isolates in clade VI (B. weihenstephanensis/B. mycoides), where none of the isolates were cytotoxic, and isolates in clade I (B. pseudomycoides), which consistently displayed cytotoxic activity. Importantly, our study highlights that B. pseudomycoides is cytotoxic toward human cells. Our results indicate that the detection of toxin genes does not provide a reliable approach to predict the pathogenic potential of B. cereus group isolates, as the presence of toxin genes is not always consistent with cytotoxicity phenotype. Overall, our results suggest that isolates from multiple B. cereus group clades have the potential to cause foodborne illness, although cytotoxicity is not always consistently found among isolates within each clade.",
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Intraclade variability in toxin production and cytotoxicity of Bacillus cereus group type strains and dairy-associated isolates. / Miller, Rachel A.; Jian, Jiahui; Beno, Sarah M.; Wiedmann, Martin; Kovac, Jasna.

In: Applied and environmental microbiology, Vol. 84, No. 6, e02479-17, 01.03.2018.

Research output: Contribution to journalArticle

TY - JOUR

T1 - Intraclade variability in toxin production and cytotoxicity of Bacillus cereus group type strains and dairy-associated isolates

AU - Miller, Rachel A.

AU - Jian, Jiahui

AU - Beno, Sarah M.

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