Bacillus cereus

Revision as of 12:43, 4 August 2015 by Rossdonaldson1 (talk | contribs) (Antibiotic SensitivitiesSanford Guide to Antimicrobial Therapy 2014)

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]

Antibiotic Sensitivities[3]

Key

  • S susceptible/sensitive (usually)
  • I intermediate (variably susceptible/resistant)
  • R resistant (or not effective clinically)
  • S+ synergistic with cell wall antibiotics
  • U sensitive for UTI only (non systemic infection)
  • X1 no data
  • X2 active in vitro, but not used clinically
  • X3 active in vitro, but not clinically effective for Group A strep pharyngitis or infections due to E. faecalis
  • X4 active in vitro, but not clinically effective for strep pneumonia

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. Takabe F, Oya M (1976). "An autopsy case of food poisoning associated with Bacillus cereus". ForensicSci 7 (2): 97–101.
  3. Sanford Guide to Antimicrobial Therapy 2014