Difference between revisions of "Bacillus cereus"

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==Background==
 
==Background==
*Gram-positive, beta-hemolytic, rod-shaped bacterium
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[[File:bcereus.png|thumb|B. cereus growing on blood agar]]
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*[[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"
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*8-16 hour incubation time
  
==Pathogenesis==
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===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.
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*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.
*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.
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*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 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.
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==Clinical Features==
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*Causes 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>
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==Differential Diagnosis==
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{{Diarrhea DDX}}
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==Management==
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Primarily supportive/symptomatic treatment, as most patients recover.
  
 
==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>
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*Most emetic patients recover within 6-24 hours
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**In some rare 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>
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==Table Overview==
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{{Clinically Relevant Bacteria}}
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==See Also==
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*[[Microbiology (Main)]]
  
 
==References==
 
==References==
<references />
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<references/>
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[[Category:ID]]

Latest revision as of 15:50, 18 August 2015

Background

B. cereus growing on blood agar
  • 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"
  • 8-16 hour incubation time

Pathogenesis

  • 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.
  • 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.

Clinical Features

Differential Diagnosis

Acute diarrhea

Infectious

Noninfectious

Watery Diarrhea

Traveler's Diarrhea

Management

Primarily supportive/symptomatic treatment, as most patients recover.

Prognosis

  • Most emetic patients recover within 6-24 hours
    • In some rare cases, the toxin can be fatal.[3]

Table Overview

See Also

References

  1. 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.
  2. Marx et al. “Cholera and Gastroenteritis caused by Noncholera Vibrio Species”. Rosen’s Emergency Medicine 8th edition vol 1 pg 1245-1246.
  3. Takabe F, Oya M (1976). "An autopsy case of food poisoning associated with Bacillus cereus". ForensicSci 7 (2): 97–101.