Genome Differences That Distinguish Bacillus anthracis from Bacillus cereus and Bacillus thuringiensis

Abstract

The three species of the group 1 bacilli, Bacillus anthracis, B. cereus, and B. thuringiensis, are genetically very closely related. All inhabit soil habitats but exhibit different phenotypes. B. anthracis is the causative agent of anthrax and is phylogenetically monomorphic, while B. cereus and B. thuringiensis are genetically more diverse. An amplified fragment length polymorphism analysis described here demonstrates genetic diversity among a collection of non-anthrax-causing Bacillus species, some of which show significant similarity to B. anthracis. Suppression subtractive hybridization was then used to characterize the genomic differences that distinguish three of the non-anthrax-causing bacilli from B. anthracis Ames. Ninety-three DNA sequences that were present in B. anthracis but absent from the non-anthrax-causing Bacillus genomes were isolated. Furthermore, 28 of these sequences were not found in a collection of 10 non-anthrax-causing Bacillus species but were present in all members of a representative collection of B. anthracis strains. These sequences map to distinct loci on the B. anthracis genome and can be assayed simultaneously in multiplex PCR assays for rapid and highly specific DNA-based detection of B. anthracis.

Diagnostic Probes for Bacillus anthracis Spores Selected from a Landscape Phage Library

“…anthracis spores are a challenge to detect because several closely related Bacillus species are ubiquitous in the environment. B. cereus, an opportunistic human pathogen, and B. thuringiensis, an insecticide, are both genetically very similar to B. anthracis (1 ). To avoid costly false alarms, a detection system must be sensitive enough to detect low concentrations of B. anthracis spores but selective enough to differentiate between B. anthracis and other closely related species.…”

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

“…30 These genetic markers provide limited specificity and require additional timeconsuming and labor-intensive post-PCR analysis steps. Other areas of the chromosome have also been investigated as potential DNA-targets for identification purposes, including the so-called BA813 [31][32][33][34][35][36][37][38] and BA5510 sequences, 19 genes bclB, 39 sap, 40,41 saspB, 5,42 and sspE, 22,43 the B-type small acid-soluble spore protein gene (SASP), 44 a glycosyltransferase group 1 family protein, 45 a protein showing similarities with an abhydrolase, 18 and several DNA loci located on prophage regions, 17 i.e., BA5345, 21 BA5357, 46 and PL3. 47 Although most of these regions have been claimed to be anthrax-specific, B. cereus strains sometimes yield false positive results.…”

“…[13][14][15] Few chromosomal sequences that provide sufficient polymorphism to unambiguously distinguish B. anthracis from its near neighbors have been identified. 14,[16][17][18][19][20][21][22] Some of these assays rely upon single-nucleotide differences for discrimination and are therefore sensitive to assay conditions and PCR cycling parameters. Small alterations in these conditions can result in the loss of specificity, especially with hydrolysis probes, i.e., TaqMan chemistry.…”

Promotion of Epithelial to Mesenchymal Transformation by Hyaluronan

“…49 SSH and AFLP have been successfully used to identify genomic sequence differences between various strains or species of bacteria. 4 ' 5 ' 10 ' 29, 44 The major drawback of this approach is that it permits identification of genomic differences only between two organisms. For instance, in order to differentiate two species, one needs to use an SSH assay to compare each strain of one species with each strain of the other species.…”