Identification of anthrax toxin genes in aBacillus cereusassociated with an illness resembling inhalation anthrax

Abstract

Bacillus anthracis is the etiologic agent of anthrax, an acute fatal disease among mammals. It was thought to differ from Bacillus cereus, an opportunistic pathogen and cause of food poisoning, by the presence of plasmids pXO1 and pXO2, which encode the lethal toxin complex and the poly-␥-D-glutamic acid capsule, respectively. This work describes a non-B. anthracis isolate that possesses the anthrax toxin genes and is capable of causing a severe inhalation anthrax-like illness. Although initial phenotypic and 16S rRNA analysis identified this isolate as B. cereus, the rapid generation and analysis of a high-coverage draft genome sequence revealed the presence of a circular plasmid, named pBCXO1, with 99.6% similarity with the B. anthracis toxin-encoding plasmid, pXO1. Although homologues of the pXO2 encoded capsule genes were not found, a polysaccharide capsule cluster is encoded on a second, previously unidentified plasmid, pBC218. A͞J mice challenged with B. cereus G9241 confirmed the virulence of this strain. These findings represent an example of how genomics could rapidly assist public health experts responding not only to clearly identified select agents but also to novel agents with similar pathogenic potentials. In this study, we combined a public health approach with genome analysis to provide insight into the correlation of phenotypic characteristics and their genetic basis.

Erratum to: Seasonal trend and clinical presentation of Bacillus cereus bloodstream infection: association with summer and indwelling catheter

“…However, these results suggest that the increase of BSI in summer was not associated with a specific strain. The contribution of common [3,5,12]. Our study was not able to explain the virulence determinants that affected the clinical presentation.…”

“…The nheABC gene is the major cytotoxic membrane-damaging factor [21]. In B. cereus food-bourne diarrhoeal disease, nheABC was considered as the main virulence factor and was found in more than 90 % of isolates [12,16,22]. nheABC was also dominant in our BSI isolates.…”

“…cereus produces several virulence factors, including toxins and enzymes [11]. Certain B. cereus isolates, closely related to B. anthracis with specific virulence genotypes, can cause severe and even fatal infections in patients who appear to be otherwise healthy [12]. Whether virulence genes of B. cereus BSI isolates determine their pathogenicity is an issue open to question because it has not yet been investigated.…”

Division of labour and terminal differentiation in a novel Bacillus thuringiensis strain

“…Moreover, the LM1212 genome contains genes for PlcR and NprR, which are quorum-sensing regulators specific to the B. cereus group bacteria (Slamti and Lereclus, 2005;Perchat et al, 2011). The sequences of the sensor regulators (PlcR and NprR) and of their cognate peptides (PapR and NprX) from LM1212 were 100% identical to those of B. cereus G9241 (data not shown), a strain encoding the entire anthrax toxin biosynthetic complex and that was responsible for a human anthrax case (Hoffmaster et al, 2004). This is surprising because PlcR-PapR and NprR-NprX are phylogenetically unrelated and these two systems are supposed to have evolved independently (Perchat et al, 2011).…”

In silico and in vitro evaluation of PCR-based assays for the detection ofBacillus anthracischromosomal signature sequences

“…5,6 The main difference between these 672 Virulence Volume 4 Issue 8 species is the presence of unique virulence plasmids. However, data gathered in the last decade have shown that B. cereus strains that contain anthrax-specific pXO-like plasmids exist [7][8][9][10][11][12] which further obscures the much intermixed phylogenetic structure of the B. cereus group. Some PCR-based assays in use for detection of B. anthracis rely on plasmid-encoded targets in conjunction with a chromosomal marker to correctly differentiate pathogenic from apathogenic B. anthracis strains and B. anthracis from non-anthracis Bacillus species, respectively (for a review see ref.…”