Toxin gene profiling of enterotoxic and emetic Bacillus cereus

• Published in: FEMS microbiology letters 2006-07, Vol.260 (2), p.232-240
• Main Authors: Ehling-Schulz, Monika, Guinebretiere, Marie-Hélène, Monthán, Amanda, Berge, Odile, Fricker, Martina, Svensson, Birgitta
• Format: Article
• Language: English
• Subjects: Bacillus cereus; Bacillus cereus - genetics; Bacillus cereus - metabolism; Bacillus cereus - pathogenicity; Bacterial Toxins - chemistry; Bacterial Toxins - genetics; Bacteriology; Base Sequence; Biological and medical sciences; Cereulide; Depsipeptides - chemistry; Depsipeptides - genetics; Depsipeptides - metabolism; Diagnostic systems; DNA, Bacterial - analysis; emetic toxin; Emetics - chemistry; Emetics - metabolism; enterotoxins; Enterotoxins - chemistry; Enterotoxins - genetics; Food; Food contamination; Food Microbiology; Food poisoning; Foodborne Diseases - diagnosis; Foodborne Diseases - microbiology; Fundamental and applied biological sciences. Psychology; Gastrointestinal diseases; Gene polymorphism; Genes; Genetic Variation; Genetics; Humans; Life Sciences; Microbiology; Microbiology and Parasitology; Molecular Sequence Data; Operons; Pathogenicity, virulence, toxins, bacteriocins, pyrogens, host-bacteria relations, miscellaneous strains; PCR assay; Phylogeny; Polymerase Chain Reaction - methods; Polymorphism; Primers; Sensitivity and Specificity; Sequence Analysis, DNA; toxin profiling; Toxins; Vomiting
• ISSN: 0378-1097; 1574-6968
• DOI: 10.1111/j.1574-6968.2006.00320.x

Abstract Very different toxins are responsible for the two types of gastrointestinal diseases caused by Bacillus cereus: the diarrhoeal syndrome is linked to nonhemolytic enterotoxin NHE, hemolytic enterotoxin HBL, and cytotoxin K, whereas emesis is caused by the action of the depsipeptide toxin cereulide. The recently identified cereulide synthetase genes permitted development of a molecular assay that targets all toxins known to be involved in food poisoning in a single reaction, using only four different sets of primers. The enterotoxin genes of 49 strains, belonging to different phylogenetic branches of the B. cereus group, were partially sequenced to encompass the molecular diversity of these genes. The sequence alignments illustrated the high molecular polymorphism of B. cereus enterotoxin genes, which is necessary to consider when establishing PCR systems. Primers directed towards the enterotoxin complex genes were located in different CDSs of the corresponding operons to target two toxin genes with one single set of primers. The specificity of the assay was assessed using a panel of B. cereus strains with known toxin profiles and was successfully applied to characterize strains from food and clinical diagnostic labs as well as for the toxin gene profiling of B. cereus isolated from silo tank populations.