The Bacillus cereus Group: Bacillus Species with Pathogenic Potential

Abstract

The “Bacillus cereus group” includes several Bacillus species with closely related phylogeny. The most well-studied members of the group, Bacillus anthracis, B. cereus, and B. thuringiensis are known for their pathogenic potential. Here we present the historical rationale for speciation and discuss shared and unique features of these bacteria. Aspects of cell morphology and physiology, and genome sequence similarity and gene synteny support close evolutionary relationships for these three species. For many strains, distinct differences in virulence factor synthesis provide facile means for species assignment. B. anthracis is the causative agent of anthrax. Some B. cereus strains are commonly recognized as food poisoning agents, but strains can also cause localized wound and eye infections as well as systemic disease. Certain B. thuringiensis strains are entomopathogens and have been commercialized for use as biopesticides, while some strains have been reported to cause infection in immunocompromised individuals. In this chapter we compare and contrast B. anthracis, B. cereus, and B. thuringiensis, including ecology, cell structure and development, virulence attributes, gene regulation and genetic exchange systems, and experimental models of disease.

Phylogenetic Analysis of Bacillus cereus sensu lato Isolates from Commercial Bee Pollen Using tRNACys-PCR

“…Several B. cereus strains have been identified as opportunistic food-borne pathogens, and several different toxins have been associated with food poisoning outbreaks caused by these strains, viz. cereulide, cytotoxin K, hemolysin BL (HBL), and non-hemolytic enterotoxin (NHE) [10,13,17,45,46]. In this regard, and in accord with other reports, bacterial members of the B. cereus group have been isolated and identified using phenotypic characteristics or molecular approaches based on 16S rRNA or MALDI-TOFF MS in bee pollen obtained from hives or commercial sources [25,47,48].…”

“…It must be noted that the existing literature suggests a high degree of genetic diversity between the various species examined here, and questions related to the taxonomy of B. anthracis, B. cereus, and B. thuringiensis continue to be argued among researchers in this field [9][10][11][12][13][14][15][16][17][18][19][20][21][22][23][24]. Additional insight into these taxonomic questions will no doubt be provided by comparative genomics, as well as by molecular discrimination analyses using prominent biomarkers such as the chaperonin protein (GroEL) and the topoisomerase (gyrB) [50].…”

The stationary phase regulator CpcR activates cry gene expression in non‐sporulating cells of Bacillus thuringiensis

“…A remarkable division of labour in bacteria has been recently illustrated by the study of a Bacillus thuringiensis strain that differentiates into two distinct subpopulations of approximately equal size during the stationary growth phase: a population forming spores and another forming non‐viable cells producing crystal inclusions (Deng et al, ). B. thuringiensis is a gram‐positive sporulating species belonging to the Bacillus cereus group that includes several closely related Bacillus species (Ehling‐Schulz, Lereclus, & Koehler, ). The most known species of this bacterial group are Bacillus anthracis , the etiological agent of anthrax, B. cereus , a foodborne pathogen responsible for food poisoning and B. thuringiensis , an insect pathogen, used worldwide for pest control.…”

“…In these strains, the crystals constitute “public goods” which benefit the sporulating bacteria when they encounter a susceptible host, while the cells that produced them cannot survive. Indeed, the toxaemia induced by the Cry proteins provides favourable conditions for spore germination and subsequent bacterial development (Ehling‐Schulz et al, ; Raymond, Johnston, Nielsen‐LeRoux, Lereclus, & Crickmore, ). In this study, we cloned and characterised the transcriptional regulator responsible for this differentiation phenomenon in the strain B. thuringiensis LM1212.…”

Complete Genome Sequence of Bacillus cereus Strain PL1, Isolated from Soil in Japan

“…T he Bacillus cereus group includes several Bacillus species with close phylogenetic relationships. Among these, the species that have been studied the most are B. anthracis, B. cereus, B. thuringiensis, B. mycoides, B. pseudomycoides, B. weihenstephanensis, B. cytotoxicus, and B. toyonensis (1)(2)(3). Because some of these species are known to be potentially pathogenic (3,4), numerous efforts have been made to clinically diagnose them.…”