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Evolution of pathogenicity in the Bacillus cereus group
Xavier Didelot1, Margaret Barker, Daniel Falush
1Department of Statistics, University of Warwick, Coventry CV4 7AL, UK. X.Didelot@warwick.ac.uk
Systematic and Applied Microbiology
|February 10, 2009
Summary
The Bacillus cereus group
Area of Science:
- Microbiology
- Evolutionary Biology
- Genomics
Background:
- The Bacillus cereus group includes soil bacteria causing diverse human diseases, from food poisoning to lethal anthrax.
- While Bacillus anthracis causes anthrax, virulence variation in other B. cereus lineages remains understudied.
- Understanding B. cereus evolution is crucial for public health due to its pathogenic potential.
Purpose of the Study:
- To reconstruct the evolutionary history of the Bacillus cereus group.
- To investigate genetic exchange and population structure among B. cereus lineages.
- To understand the evolutionary basis of virulence in B. cereus and B. anthracis.
Main Methods:
- Multi-locus sequence analysis of 667 Bacillus cereus group strains.
- Phylogenetic reconstruction to determine evolutionary history and clade structure.
- Analysis of recombination patterns and gene flow between bacterial clades.
Main Results:
- Confirmed three major clades within the Bacillus cereus group.
- Bacillus anthracis and emetic toxin-producing B. cereus strains exhibit clonal structure within clade 1.
- Partial barriers to gene flow exist between clades, with recent external strain imports into clade 1.
Conclusions:
- Bacillus cereus pathogenic strains are opportunistic, with typical recombination rates.
- Evolutionary dynamics, including recent gene flow shifts, influence the pathogenicity of B. cereus group strains.
- Phylogenetic and genetic exchange analyses provide insights into the emergence and spread of Bacillus cereus-related diseases.
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