Examine individual changes

'{{italic title}} {{Taxobox | name = ''Bacillus cereus'' | image = Bacillus_cereus_01.png | image_width = 240px | image_caption = ''B. cereus'' colonies 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 (epidemiology)|endemic]], [[soil]]-dwelling, [[Gram-positive bacteria|Gram-positive]], [[Bacillus|rod-shaped]], [[hemolysis (microbiology)|beta hemolytic]] [[bacteria|bacterium]]. Some strains are harmful to humans and cause [[foodborne illness]], while other strains can be beneficial as [[probiotics]] for animals.<ref>{{cite book | author = Ryan KJ; Ray CG (editors) | title = Sherris Medical Microbiology | edition = 4th | publisher = McGraw Hill | year = 2004 | isbn = 0-8385-8529-9 }}</ref> ''B. cereus'' bacteria are [[facultative anaerobe]]s, and like other members of the genus ''[[Bacillus]]'' can produce protective [[endospore]]s. ==Symbiosis== ''B. cereus'' competes with other microorganisms such as ''[[Salmonella]]'' and ''[[Campylobacter]]'' in the [[Gut (zoology)|gut]], so its presence reduces the numbers of those microorganisms. In food animals such as [[chickens]]<ref>{{cite journal | last = Vilà | first = B | authorlink = | coauthors = A. Fontgibell, I. Badiola, E. Esteve-Garcia, G. Jiménez, M. Castillo and J. Brufau | title = Reduction of ''Salmonella enterica'' var. ''Enteritidis'' colonization and invasion by ''Bacillus cereus'' var. ''toyoi'' inclusion in poultry feeds | journal = Poultry Science | volume = 88 | issue = 55 | pages = 975–9 | publisher = HighWire Press | location = | date = 2009 | url = http://ps.fass.org/cgi/content/full/88/5/975 | issn = | doi = 10.3382/ps.2008-00483 | id = | accessdate = 14 May 2009 }} </ref>, [[rabbit]]s<ref>{{cite journal | last = Bories | first = Georges | authorlink = | coauthors = Paul Brantom, Joaquim Brufau de Barberà, Andrew Chesson, Pier Sandro Cocconcelli, Bogdan Debski, Noël Dierick, Jürgen Gropp, Ingrid Halle, Christer Hogstrand, Joop de Knecht, Lubomir Leng, Sven Lindgren, Anne-Katrine Lundebye Haldorsen, Alberto Mantovani, Miklós Mézes, Carlo Nebbia, Walter Rambeck, Guido Rychen, Atte von Wright and Pieter Wester | title = Safety and efficacy of the product Toyocerin (Bacillus cereus var. toyoi) as feed additive for rabbit breeding does - Scientific Opinion of the Panel on Additives and Products or Substances used in Animal Feed | journal = | volume = | issue = | pages = | publisher = European Food Safety Authority | location = | date = 9 December 2008 | url = http://www.efsa.europa.eu/cs/BlobServer/Scientific_Opinion/feedap_op_ej913_toyocerin_en,3.pdf?ssbinary=true | issn = | doi = | id = EFSA-Q-2008-287 | accessdate = 14 May 2009 }} </ref> and [[pig]]s,<ref>{{cite journal | last = Bories | first = Georges | authorlink = | coauthors = Paul Brantom, Joaquim Brufau de Barberà, Andrew Chesson, Pier Sandro Cocconcelli, Bogdan Debski, Noël Dierick, Anders Franklin, Jürgen Gropp, Ingrid Halle, Christer Hogstrand, Joop de Knecht, Lubomir Leng, Anne-Katrine Lundebye Haldorsen, Alberto Mantovani, Miklós Mézes, Carlo Nebbia, Walter Rambeck, Guido Rychen, Atte von Wright and Pieter Wester | title = Opinion of the Scientific Panel on Additives and Products or Substances used in Animal Feed on the safety and efficacy of the product Toyocerin (Bacillus cereus var. Toyoi) as a feed additive for sows from service to weaning, in accordance with Regulation (EC) No 1831/2003 | journal = | volume = | issue = | pages = | publisher = European Food Safety Authority | location = | date = EFSA-Q-2006-037 | url = http://www.efsa.europa.eu/cs/BlobServer/Scientific_Opinion/feedap_op_ej458_toyocerin_sows_en.pdf?ssbinary=true | issn = | doi = | id = | accessdate = 14 May 2009 }} </ref> some harmless strains of ''B. cereus'' are used as a [[probiotic]] [[feed additive]] to reduce ''Salmonella'' in the [[intestine]]s and [[cecum]]. This improves the animals' growth as well as food safety for humans who eat their meat. ==Pathogenesis== ''B. cereus'' is responsible for a minority of foodborne illnesses (2&ndash;5%), causing severe [[nausea]], [[vomiting]] and [[diarrhea]].<ref>{{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}}</ref> ''Bacillus'' foodborne illnesses occur due to survival of the bacterial endospores when food is improperly cooked.<ref>{{cite book | author = Turnbull PCB | title = Bacillus. ''In:'' Baron's Medical Microbiology ''(Barron S ''et al.'', eds.)| edition = 4th | 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 }} </ref> This problem is compounded when food is then improperly [[refrigeration|refrigerated]], allowing the endospores to germinate.<ref>{{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}}</ref> Bacterial growth results in production of [[enterotoxin]]s, one of which is highly resistant to heat and to [[pH]] between 2 and 11;<ref name=Todar /> ingestion leads to two types of illness, diarrheal and emetic (vomiting) syndrome.<ref>{{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}}</ref> :*The diarrheal type is associated with a wide-range of foods, has an 8- to 16.5-hour [[incubation period|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]]''.<ref name=Todar>{{cite web | title=''Bacillus cereus'' | work=Todar's Online Textbook of Bacteriology | url=http://textbookofbacteriology.net/B.cereus.html | accessdate=2009-09-19}}</ref> :*The emetic form is commonly caused by rice that is not cooked for a time and temperature sufficient 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 1&ndash;5 hours after consumption. It can be difficult to distinguish from other short-term bacterial foodborne pathogens such as ''[[Staphylococcus aureus]]''.<ref name=Todar />If rice is cooked at, or over, 100 degrees [[Celsius]] for 20 minutes or more ''Bacillus cereus'' cannot survive{{Verify source|date=February 2010}}, therefore eliminating possible food poisoning. The diarrhetic syndromes observed in patients is thought to stem from the three toxins [[Hemolysin BL]] Hbl, [[Nonhemolytic Enterotoxin]] Nhe and [[Cytotoxin K]] CytK <ref>Enterotoxigenic Profiles of Food-Poisoning and Food-Borne Bacillus cereus Strains Marie-Hélène Guinebretière,* Véronique Broussolle, and Christophe Nguyen-TheInstitut National de la Recherche Agronomique, UMR A408 Sécurité et Qualité des Produits d'Origine Végétale, INRA, Domaine Saint-Paul, Site Agroparc, F-84914 Avignon Cedex 9, France. PMCID: PMC120679 </ref>. The ''nhe''/''hbl''/''cytK'' genes are located on the chromosome of the bacteria. Transcription of these genes is controlled by PlcR. These genes occur as well in the toxonomically related ''B. thuringensis'' and ''B. anthracis''. These enterotoxins are all produced in the small intestine of the host, thus thwarting the issue of digestion by host endogenous enzymes. The Hbl and Nhe toxins are pore-forming toxins closely related to [[ClyA]] of ''[[E. coli]]''. The proteins exhibit a conformation known as "beta-barrel" that can insert into cellular membranes due to a [[hydrophobic]] exterior, thus creating pores with [[hydrophilic]] interiors. The effect is loss of cellular [[membrane potential]] and eventually cell death. CytK is a pore-forming protein more related to other hemolysins. It was previously thought that the timing of the toxin production might be responsible for the two different courses of disease, 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 contains 3 repeats of 4 amino acids (similar to [[Valinomycin]] produced by ''[[Streptomyces griseus]]'') produced by [[nonribosomal peptide|nonribosomal peptide synthesis (NRPS)]]. Cereulide is believed to activate 5-HT3 ([[serotonin]]) receptors leading to increased [[afferent]] [[vagus nerve stimulation]].<ref>{{cite journal | author=Agata N, Ohta M, Mori M, Isobe M | title=A novel dodecadepsipeptide, cereulide, is an emetic toxin of Bacillus cereus. | journal=FEMS Microbiol Lett | year=1995 | pages=17–20 | volume=129 | issue=1 | pmid=7781985}}</ref> It was shown independently by two research groups to be encoded on multiple [[plasmid]]s: pCERE01<ref>{{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}}</ref> or pBCE4810.<ref>{{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}}</ref> Plasmid pBCE4810 shares homology with the ''[[Bacillus anthracis]]'' virulence plasmid pXO1, which encodes the [[anthrax toxin]]. Periodontal isolates of ''B. cereus'' also possess distinct pXO1-like plasmids. ''B. cereus'' is also known to cause chronic skin infections that are difficult to eradicate though less aggressive than ''[[necrotizing fasciitis]]''. ''B. cereus'' can also cause [[keratitis]].<ref name="pmid11581057">{{cite journal |author=Pinna A, Sechi LA, Zanetti S, ''et al.'' |title=Bacillus cereus keratitis associated with contact lens wear |journal=Ophthalmology |volume=108 |issue=10 |pages=1830–4 |year=2001 |month=October |pmid=11581057 |doi= 10.1016/S0161-6420(01)00723-0|url=http://linkinghub.elsevier.com/retrieve/pii/S0161-6420(01)00723-0}}</ref> ==References== <!-- --------------------------------------------------------------- See http://en.wikipedia.org/wiki/Wikipedia:Footnotes for a discussion of different citation methods and how to generate footnotes using the <ref> & </ref> tags and the {{Reflist}} template -------------------------------------------------------------------- --> {{Reflist|2}} {{Commons category}} {{Gram-positive bacterial diseases}} {{DEFAULTSORT:Bacillus Cereus}} [[Category:Bacillaceae]] [[Category:Foodborne illnesses]] [[Category:Sequenced genomes]] [[ca:Bacillus cereus]] [[da:Bacillus cereus]] [[de:Bacillus cereus]] [[es:Bacillus cereus]] [[fr:Bacillus cereus]] [[it:Bacillus cereus]] [[nl:Bacillus cereus]] [[ja:セレウス菌]] [[no:Bacillus cereus]] [[pt:Bacillus cereus]] [[ru:Bacillus cereus]] [[fi:Bacillus cereus]] [[sv:Bacillus cereus]] [[uk:Bacillus cereus]] [[zh:蠟樣芽孢桿菌]]'