Bacillus cereus: Difference between revisions
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==Background== | ==Background== | ||
* | *Gram-positive, beta-hemolytic, rod-shaped bacterium | ||
*Known for causing foodborne illness in humans, though some strains are probiotic | *Known for causing foodborne illness in humans, though some strains are probiotic | ||
*Classically associated with "fried rice syndrome" | *Classically associated with "fried rice syndrome" | ||
[[File:bcereus.png|thumb|B. cereus growing on blood agar]] | |||
==Pathogenesis== | |||
B. cereus is responsible for a minority of foodborne illnesses, causing severe nausea, vomiting, and diarrhea.<ref> Kotiranta A, Lounatmaa K, Haapasalo M (2000). "Epidemiology and pathogenesis of Bacillus cereus infections". Microbes Infect 2 (2): 189–98. doi:10.1016/S1286-4579(00)00269-0. PMID 10742691.</ref> Bacillus foodborne illnesses occur due to survival of endospores when food is improperly cooked. Bacterial growth results in production of enterotoxins, one of which is heat- and acid-stable (pH 2 to 11); ingestion leads to two types of illness: diarrheal and emetic. | |||
*The diarrheal type is associated with a wide range of foods, has an 8-16 hour incubation time, and is associated with diarrhea and gastrointestinal pain. | |||
*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 which is not inactivated by later reheating. This form leads to nausea and vomiting one to five hours after consumption. It can be difficult to distinguish from other short-term bacterial foodborne intoxications such as by Staphylococcus aureus. | |||
* | |||
==Prognosis== | ==Prognosis== | ||
Most emetic patients recover within six to 24 hours but in some cases, the toxin can be fatal.<ref> Takabe F, Oya M (1976). "An autopsy case of food poisoning associated with Bacillus cereus". ForensicSci 7 (2): 97–101.</ref> | |||
==References== | ==References== | ||
<references/> | <references /> | ||
Revision as of 20:21, 17 August 2015
Background
- Gram-positive, beta-hemolytic, rod-shaped bacterium
- Known for causing foodborne illness in humans, though some strains are probiotic
- Classically associated with "fried rice syndrome"
Pathogenesis
B. cereus is responsible for a minority of foodborne illnesses, causing severe nausea, vomiting, and diarrhea.[1] Bacillus foodborne illnesses occur due to survival of endospores when food is improperly cooked. Bacterial growth results in production of enterotoxins, one of which is heat- and acid-stable (pH 2 to 11); ingestion leads to two types of illness: diarrheal and emetic.
- The diarrheal type is associated with a wide range of foods, has an 8-16 hour incubation time, and is associated with diarrhea and gastrointestinal pain.
- 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 which is not inactivated by later reheating. This form leads to nausea and vomiting one to five hours after consumption. It can be difficult to distinguish from other short-term bacterial foodborne intoxications such as by Staphylococcus aureus.
Prognosis
Most emetic patients recover within six to 24 hours but in some cases, the toxin can be fatal.[2]
References
- ↑ Kotiranta A, Lounatmaa K, Haapasalo M (2000). "Epidemiology and pathogenesis of Bacillus cereus infections". Microbes Infect 2 (2): 189–98. doi:10.1016/S1286-4579(00)00269-0. PMID 10742691.
- ↑ Takabe F, Oya M (1976). "An autopsy case of food poisoning associated with Bacillus cereus". ForensicSci 7 (2): 97–101.