B.<unk>  is responsible for a minority of foodborne illnesses (2–5%), causing severe nausea, vomiting, and diarrhea.<unk>  foodborne illnesses occur due to survival of the bacterial endospores when infected food is not, or is inadequately, cooked. Cooking temperatures less than or equal to allow some B.<unk>  spores to survive. This problem is compounded when food is then improperly refrigerated, allowing the endospores to germinate. Cooked foods not meant for either immediate consumption or rapid cooling and refrigeration should be kept at temperatures below or above . Germination and growth generally occur between 10 °C and 50 °C, though some strains can grow at low temperatures. Bacterial growth results in production of enterotoxins, one of which is highly resistant to heat and acids (pH levels between 2 and 11); ingestion leads to two types of illness: diarrheal and emetic (vomiting) syndrome. * The diarrheal type is associated with a wide range of foods, has an 8-to-16-hour incubation time, and is associated with diarrhea and gastrointestinal pain. Also known as the 'long-incubation' form of B.<unk>  food poisoning, it might be difficult to differentiate from poisoning caused by Clostridium perfringens. Enterotoxin can be inactivated after heating at for 5 minutes, but whether its presence in food causes the symptom is unclear, since it degrades in stomach enzymes; its subsequent production by surviving B.<unk>  spores within the small intestine may be the cause of illness. * The 'emetic' form is commonly caused by rice cooked for a time and temperature insufficient to kill any spores present, then improperly refrigerated. It can produce a toxin,<unk> ide, which is not inactivated by later reheating. This form leads to nausea and vomiting 1–5 hours after consumption. Distinguishing from other short-term bacterial foodborne intoxications such as by Staphylococcus aureus can be difficult. Emetic toxin can withstand for 90 minutes. The diarrhetic syndromes observed in patients are thought to stem from the three toxins: hemolysin BL (Hbl), nonhemolytic enterotoxin (Nhe), and cytotoxin K (CytK). The nhe/hbl/cytK genes are located on the chromosome of the bacteria. Transcription of these genes is controlled by PlcR. These genes occur in the taxonomically related B. thuringiensis and B. anthracis, as well. These enterotoxins are all produced in the small intestine of the host, thus thwarting digestion by host endogenous enzymes. The Hbl and Nhe toxins are pore-forming toxins closely related to ClyA of E. coli. The proteins exhibit a conformation known as a "beta-barrel" that can insert into cellular membranes due to a hydrophobic exterior, thus creating pores with hydrophilic interiors. The effect is loss of cellular membrane potential and eventually cell death. CytK is a pore-forming protein more related to other hemolysins. The timing of the toxin production was previously thought to be possibly responsible for the two different courses of disease, but in fact the emetic syndrome is caused by a toxin,<unk> ide, found only in emetic strains and is not part of the "standard toolbox" of B.<unk> .<unk> ide is a cyclic polypeptide containing three repeats of four amino acids: -oxy-—-—-oxy-—- (similar to valinomycin produced by Streptomyces griseus) produced by nonribosomal peptide synthesis.<unk> ide is believed to bind to 5-hydroxytryptamine 3 (5-HT3) serotonin receptors, activating them and leading to increased afferent vagus nerve stimulation. It was shown independently by two research groups to be encoded on multiple plasmids: pCERE01 or pBCE4810. Plasmid pBCE4810 shares homology with the B. anthracis virulence plasmid pXO1, which encodes the anthrax toxin. Periodontal isolates of B.<unk>  also possess distinct pXO1-like plasmids. Like most of cyclic peptides containing nonproteogenic amino acids,<unk> ide is resistant to heat, proteolysis, and acid conditions. B.<unk>  is also known to cause difficult-to-eradicate chronic skin infections, though less aggressive than necrotizing fasciitis. B.<unk>  can also cause keratitis. A case study was published in 2019 of a catheter-related bloodstream infection of B.<unk>  in a 91-year-old male previously being treated with hemodialysis via PermCath for end-stage renal disease. He presented with chills, tachypnea, and high-grade fever, his white blood cell count and high-sensitivity C-reactive protein (CRP) were significantly elevated, and CT imaging revealed a thoracic aortic aneurysm. He was successfully treated for the aneurysm with intravenous vancomycin, oral fluoroquinolones, and PermCath removal.
Bacillus cereus
Clostridium perfringens
Salmonella enterica subsp. enterica
Vibrio vulnificus
Vibrio cholerae
Escherichia coli
Salmonella
Listeria monocytogenes