Bacillus cereus

Taxobox
color = lightgrey
name = "Bacillus cereus"

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image_width = 240px
image_caption = "B. cereus" on sheep blood agar plate.
regnum = Bacteria
phylum = Firmicutes
classis = Bacilli
ordo = Bacillales
familia = Bacillaceae
genus = "Bacillus"
species = "cereus"
binomial = "Bacillus cereus"
binomial_authority = Frankland & Frankland 1887

"Bacillus cereus" is an endemic, soil-dwelling, Gram-positive, rod-shaped, beta hemolytic bacteria that causes foodborne illness. [cite book | author = Ryan KJ; Ray CG (editors) | title = Sherris Medical Microbiology YOOR MUM | edition = 4th ed. | publisher = McGraw Hill | year = 2004 | id = ISBN 0-8385-8529-9 ] It is the cause of "Fried Rice Syndrome". "B. cereus" bacteria are facultative aerobes, and like other members of the genus "Bacillus" can produce protective endospores.

Pathogenesis

"B. cereus" is responsible for a minority of foodborne illnesses (2–5%), causing severe nausea, vomiting and diarrhea. [cite journal | author=Kotiranta A, Lounatmaa K, Haapasalo M | title=Epidemiology and pathogenesis of "Bacillus cereus" infections | journal=Microbes Infect | year=2000 | pages=189–98 | volume=2 | issue=2 | pmid=10742691 | doi = 10.1016/S1286-4579(00)00269-0 ] Generally speaking, "Bacillus" foodborne illnesses occur due to survival of the bacterial endospores when food is improperly cooked. [cite book | author = Turnbull PCB | title = Bacillus. "In:" Baron's Medical Microbiology "(Barron S "et al", eds.)| edition = 4th ed. | publisher = Univ of Texas Medical Branch | year = 1996 | id = [http://www.ncbi.nlm.nih.gov/books/bv.fcgi?rid=mmed.section.935#939 (via NCBI Bookshelf)] ISBN 0-9631172-1-1 ] This problem is compounded when food is then improperly refrigerated, allowing the endospores to germinate. [cite journal | author=McKillip JL | title=Prevalence and expression of enterotoxins in "Bacillus cereus" and other "Bacillus" spp., a literature review | journal=Antonie Van Leeuwenhoek | year=2000 | pages=393–9 | volume=77 | issue=4 | pmid=10959569 | doi = 10.1023/A:1002706906154 ] Bacterial growth results in production of enterotoxin, and ingestion leads to two types of illness, diarrheal and emetic (vomiting) syndrome. [cite journal | author=Ehling-Schulz M, Fricker M, Scherer S | title="Bacillus cereus", the causative agent of an emetic type of food-borne illness | journal=Mol Nutr Food Res | year=2004 | pages=479–87 | volume=48 | issue=7 | pmid=15538709 | doi = 10.1002/mnfr.200400055 ] :*The diarrheal type is associated with a wide-range of foods, has an 8–16.5 hour incubation time and is associated with diarrhea and gastrointestinal pain. Also known as the "long-incubation" form of "B. cereus" food poisoning, it might be difficult to differentiate from poisoning caused by "Clostridium perfringens".cite web | title="Bacillus cereus" | work=Todar's Online Textbook of Bacteriology | url=http://textbookofbacteriology.net/B.cereus.html | accessdate=2006-04-10] :*In the emetic form, rice that is cooked then improperly refrigerated is common cause, leading to nausea and vomiting 1–5 hours after consumption. This form can be difficult to distinguish from other short-term bacterial foodborne pathogens (e.g. "Staphylococcus aureus").It was previously thought that the timing of the toxin production might be responsible for the two different types, but in fact the emetic syndrome is caused by a toxin called cereulide that is found only in emetic strains and is not part of the 'standard toolbox' of "B. cereus". Cereulide a dodecadepsipeptide produced by non-ribosomal peptide synthesis (NRPS), which is somewhat unusual in itself. It was shown independently by two research groups to be encoded on a plasmid, which is called pCERE01 [cite journal | author=Hoton FM, Andrup L, Swiecicka I, Mahillon J | title=The cereulide genetic determinants of emetic "Bacillus cereus" are plasmid-borne. | journal=Microbiology | year=2005 | pages=2121–4 | volume=151 | issue=7 | pmid=16000702 | doi = 10.1099/mic.0.28069-0 ] or pBCE4810. [cite journal | author=Ehling-Schulz M, Fricker M, Grallert H, Rieck P, Wagner M, Scherer S | title=Cereulide synthetase gene cluster from emetic "Bacillus cereus": structure and location on a mega virulence plasmid related to "Bacillus anthracis" toxin plasmid pXO1. | journal=BMC Microbiol | year=2006 | volume=6 | issue=20 | pmid=16512902 | pages = 20 | doi = 10.1186/1471-2180-6-20 ] Interestingly, this plasmid shares a common backbone with the virulence plasmid pXO1, which encodes the anthrax toxin genes in "B. anthracis", but with a different pathogenicity island. Periodontal isolates of "B. cereus" also possess distinct pXO1-like plasmids."B. cereus" is also known to cause skin infections that can be quite lengthy, difficult to eradicate, and damaging, though less aggressive than the more notorious "Necrotizing fasciitis"

References