Bacillus cereus: Difference between revisions

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==Background==
==Background==
*Gram-positive, beta-hemolytic, rod-shaped bacterium
[[File:bcereus.png|thumb|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
*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]]
*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==
*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>
 
==Differential Diagnosis==
{{Diarrhea DDX}}


==Pathogenesis==
==Management==
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.
Primarily supportive/symptomatic treatment, as most patients recover.
*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>
*Most emetic patients recover within 6-24 hours
**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>
 
==Table Overview==
{{Clinically Relevant Bacteria}}
 
==See Also==
*[[Microbiology (Main)]]


==References==
==References==
<references />
<references/>


[[Category:ID]]
[[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

Gram Positives
Cocci
Clusters
Pairs/Chains
Other
Rods
Gram Negatives
Cocci
Rods
Lactose Fermenters
Lactose Non-Fermenters
Other
Rods/Cocci
Anaerobes

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.
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