The phylogeny of Bacillus cereus sensu lato

Richard T. Okinaka, Paul S Keim

Research output: Contribution to journalArticle

26 Scopus citations

Abstract

The three main species of the Bacillus cereus sensu lato, B. cereus, B. thuringiensis, and B. anthracis, were recognized and established by the early 1900s because they each exhibited distinct phenotypic traits. B. thuringiensis isolates and their parasporal crystal proteins have long been established as a natural pesticide and insect pathogen. B. anthracis, the etiological agent for anthrax, was used by Robert Koch in the 19th century as a model to develop the germ theory of disease, and B. cereus, a common soil organism, is also an occasional opportunistic pathogen of humans. In addition to these three historical species designations, are three less-recognized and -understood species: B. mycoides, B. weihenstephanensis, and B. pseudomycoides. All of these "species" combined comprise the Bacillus cereus sensu lato group. Despite these apparently clear phenotypic definitions, early molecular approaches to separate the first three by various DNA hybridization and 16S/23S ribosomal sequence analyses led to some "confusion" because there were limited differences to differentiate between these species. These and other results have led to frequent suggestions that a taxonomic change was warranted to reclassify this group to a single species. But the pathogenic properties of B. anthracis and the biopesticide applications of B. thuringiensis appear to "have outweighed pure taxonomic considerations" and the separate species categories are still being maintained. B. cereus sensu lato represents a classic example of a now common bacterial species taxonomic quandary.

Original languageEnglish (US)
Article numberTBS-0012-2012
JournalMicrobiology spectrum
Volume4
Issue number1
DOIs
StatePublished - 2016

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ASJC Scopus subject areas

  • Physiology
  • Ecology
  • Immunology and Microbiology(all)
  • Genetics
  • Cell Biology
  • Microbiology (medical)
  • Infectious Diseases

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