9/21/2016 Relevance Two Types of Toxins About 27,000 cases a year Emetic(vomiting】 Enterotoxin(diarrheal) in the US FDOD ·Produced by cells ·Produced by the .<2%of foodborne illnesses 交FOISONNG growing in the food bacteria growing in reported in the US CAN Acts fast within 0.5- the small intestines 6 hours after Prevalence in Europe is ·Acts longer,6-14 ingestion hours after ingestion 30% B.R5 ·Heat and acid stable ·Heat labile Minor foodborne pathogen Associated with Associated with Low incidence reflects that starchy foods proteinaceous foods it is not a notifiable disease Both types of illnesses are mild,brief, and self-limiting B.cereus does not compete well with other bacteria Characteristics If the food is heated,vegetative cells die and Bacillus-spore-forming,aerobic the spores germinate and grow rod-shaped bacterium If the food is heated again,the vegetative cells 16S ribosomal RNA sequences identify die and the emetic toxin remains active about 16 genera or rRNA groups of Bacillus Outbreaks are associated with meats,gravies Bacillus cereus"group"includes B. fried rice,pasta,sauces,puddings,and dairy anthracis,B.cereus,B.mycoides,B. products thuringiensis,B.pseudomycoides,and B. 17%of fish sampled identified weihenstephanensis(psychrotrophic) B.cereusand half produce the two toxins -differentiated by the toxins they produce 29/21/2016 2 Relevance • About 27,000 cases a year in the US • < 2% of foodborne illnesses reported in the US • Prevalence in Europe is 30% • Minor foodborne pathogen • Low incidence reflects that it is not a notifiable disease Two Types of Toxins Emetic (vomiting) • Produced by cells growing in the food • Acts fast within 0.5- 6 hours after ingestion • Heat and acid stable • Associated with starchy foods Enterotoxin (diarrheal) • Produced by the bacteria growing in the small intestines • Acts longer, 6-14 hours after ingestion • Heat labile • Associated with proteinaceous foods Both types of illnesses are mild, brief, and self-limiting • B. cereus does not compete well with other bacteria • If the food is heated, vegetative cells die and the spores germinate and grow • If the food is heated again, the vegetative cells die and the emetic toxin remains active • Outbreaks are associated with meats, gravies, fried rice, pasta, sauces, puddings, and dairy products • 17% of fish sampled identified B. cereus and half produce the two toxins Characteristics • Bacillus – spore-forming, aerobic rod-shaped bacterium • 16S ribosomal RNA sequences identify about 16 genera or rRNA groups of Bacillus • Bacillus cereus “group” includes B. anthracis, B. cereus, B. mycoides, B. thuringiensis, B. pseudomycoides, and B. weihenstephanensis (psychrotrophic) - differentiated by the toxins they produce