Talk:Bacillus cereus

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Comments[edit]

Text from a flashcard I wrote. Update article as needed. maveric149
Bacillus cereus Food Poisoning

1) Properties of B. cereus

2) Two types are....

3) Most US outbreaks are which type

4) Onset time of #3

5) Symptoms of #3

6) Toxin stability of #3

7) M.W. of toxin

8) Rabbit ileal loop test

5/07/01

1) Gram & catalase +, spore forming facultative anaerobic rod

2) staph-like & perfringens-like

3) staph-like (usually from fried rice)

4) 1-6 hrs

5) vomiting,nausea,diarrhea,cramps

6) heat stable

7) 5,000 (not antigenic)

8) negative

Gram status[edit]

I've reverted the recent edits made by 192.203.222.78 regarding Gram status as I've been unable to find a source confirming B. cereus as Gram-variable—all of my texts says G+ve (as does my personal experience with Bacilllus strains). With a reputable source (i.e. one whose conclusion isn't drawn from technical errors like old cultures, poor technique, etc), I'm willing to talk.... MarcoTolo 20:21, 12 April 2006 (UTC)[reply]

Bacteria of the genus Bacillus are Gram positive... I'm pretty sure Gram variable bacteria are the result of poor technique... Also, do you think B. cereus will grow on a media that is 7.5% salt (MSA)?

Bacillus cereus, and indeed the entire Bacillus genus is strictly Gram-positive. Maybe confusion arose from the fact that sometimes rod-shaped bacteria are described as bacilli regardless of their Gram staining. Regarding salt medium, 7.5% seems a bit high for B. cereus. But some of its relatives can grow on that ; for example in the lab we've got an Oceanobacillus that grows on high salt medium, up to 10 or 15% IIRC. IGollum 01:02, 15 June 2007 (UTC)[reply]

B. cereus definitely does not grow in 7.5% NaCl. In general, Staphylococci are the only common species that will grow in a salt concentration that high. Wikipedia has a good article on Mannitol Salt Agar which points this out; that medium is made with salt in order to be selective for staph. (Note that although B. cereus cannot ferment mannitol, it's the salt concentration that is relevant here, because MSA does contain other nutrients the species can survive on.) —Preceding unsigned comment added by 99.183.213.175 (talk) 06:16, 28 July 2009 (UTC)[reply]

B. cereus group, toxins, virulence and plasmids[edit]

Some suggestions for the development of this and related pages. First, we need to disambiguate the B. cereus sensu stricto species from the B. cereus group. This may require linking to a discussion of the definitions of bacterial species in light of horizontal gene transfer. B. cereus group species differ mainly by their plasmid content, and a few highly specific chromosomal differences, like the conserved point mutation in the plcR gene of B. anthracis.

Secondly, it should be made clear that the basic plasmid-less bug is an opportunistic pathogen that has an array of enterotoxins and so on, but it doesn't do much damage to healthy people. True pathogenicity is conferred in all cases by toxins on plasmids. Crystal toxins on pBtoxis etc. for B. thuringiensis, the tripartite anthrax toxin on pXO1 for B. anthracis. In B. cereus sensu stricto, it has been shown recently that emetic syndrome is caused by a toxin on a plasmid, pCERE01 (annoyingly, it has been given different names by two different groups), which has a lot of its sequence in common with pXO1 but with a different pathogenicity island. Periodontal isolates also possess distinct pXO1-like plasmids.

In addition, the conjugative plasmids and a few other mobile genetic elements should be evoked as they can be involved in the spread of virulence determinants and constitute a bit of a sore point for classification in the B. cereus family.

IGollum 01:17, 15 June 2007 (UTC)[reply]

So fried rice syndrome should be removed immediately. This is in reference to an isolated incident. That's like saying getting hit by a car is called 1998 Chevy Lumina Syndrome. ---Jon _____________

"Bacillus cereus is a facultative aerobe"... no such class for aerotollerance. maybe try facultative anaerobe.... —Preceding unsigned comment added by 71.143.153.250 (talk) 19:31, 6 April 2008 (UTC)[reply]

Heat stability[edit]

The article speaks only about "improper cooking", but does not say what might be "proper cooking". Someone might think 100 °C is enough. [1]
Bork (talk) 14:03, 30 August 2008 (UTC)[reply]

"proper cooking"? Currently a sentence reads, "If rice is cooked at, or over, 100 degrees Celsius for 20 minutes or more Bacillus cereus cannot survive[verification needed], therefore eliminating possible food poisoning." Because of the verification needed, I propose changing the sentence to read as: Bacillus cereus spores survive the cooking of rice in boiling water, and the spores can germinate and grow either during a slow cooling process or storage at room temperature, thus it is recommended that all cooked rice be stored either in a cold refrigerator or above 60°C cite. For certain food styles such as sushi where storage of cooked rice at room temperature is required, a Hazard Analysis and Critical Control Point (HACCP) procedure has been devised which coats boiled rice that has been quickly pre-cooled to room temperature within a 30-minute time-window with a 4.47% vinegar, 3.63% sugar, and 1.23% salt mixture to reduce the rice's pH below 4.4. It is claimed this room temperature rice will be safe to consume for 24 hours, after which disposal is required.cite 2 Gzuufy (talk) 01:40, 8 August 2010 (UTC)[reply]

A partial cite for the sentence as it is currently written. The cite says, "Temperatures under 212°F can allow some of the spores to survive" (in the sub-section Control and Treatment). On the prior page for another bacillus the text asserts boiling for 30 minutes kills its spores. Gzuufy (talk) 02:37, 8 August 2010 (UTC)[reply]

Broken doi source[edit]

Hey all! The doi on the following citation appears to be dead:

Asaeda, Glenn; Caicedow, Gilbert; Swanson, Christopher (December 2005). "Fried Rice Syndrome". Journal of Emergency Medical Services. 30 (12): 30–2. doi:10.1016/S0197-2510(05)70258-8 (inactive 22 January 2016). ISSN 0197-2510. PMID 16373130.{{cite journal}}: CS1 maint: DOI inactive as of January 2016 (link)

So I went to follow-up and find the actual doi, but I can't find it anywhere. Actually I can't find the article online anywhere. Is anyone able to locate this? Maybe it only exists in print and as such has no doi? I hope someone else can solve the mystery. Thanks guys! Ajpolino (talk) 05:18, 7 February 2016 (UTC)[reply]

@Ajpolino: I saw your note here and decided to investigate. To the best of my searching abilities, the article is not available online, although it is indexed in PubMed and other places. Several sources claim to link to the full text online article because JEMS publishes full text online for free. However, the JEMS online archives only go back to 2008, while this article is from 2005. I have no idea why there was a DOI included in the original citation, and as you noted it doesn't work at all, so I have removed it. Fortunately, I was able to track the article down in a library and can attest that it does exist and supports the cited statement. It's actually quite a good, simple source for the practical side of B. cereus food poisoning, and I might use it to improve the article a bit if I have time later. Thanks for pointing this out! A2soup (talk) 03:00, 15 February 2016 (UTC)[reply]

@A2soup: Great! Mystery solved!! Ajpolino (talk) 03:02, 15 February 2016 (UTC)[reply]

Pathology of ingested spores[edit]

Is there scientific consensus around whether or not ingesting only spores (not vegetative cells) can cause foodborne illness? Some sources seem to suggest that germination in the small intestine is possible:

But others either dispute that germination is possible, or claim that spores are not present in food in adequate numbers to cause disease on their own. Moreover, most all food safety procedures focus on preventing germination and growth, not eliminating spores.

RickScott (talk) 15:20, 18 April 2020 (UTC)[reply]

In the gastrointestinal tract (small intestine), vegetative cells, ingested as viable cells or spores, produce and secrete a protein enterotoxin and induce a diarrheal syndrome, whereas emetic toxin, a plasmid-encoded cyclic peptide (cereulide), is produced in food products and ingested as a formed toxin.

[2] Reverting your "dubious". Ratel 🌼 (talk) 06:28, 19 April 2020 (UTC)[reply]

Although the presence of vegetative forms of B. cereus in food is always necessary for foodborne disease to occur...

[3]

We did not find detectable amounts of vegetative cells in intestinal samples... Our results indicate that Bacillus is present in the intestinal tract solely as spores...

[4] It doesn't sound to me like there's agreement that spores can germinate in sufficient number in the small intestine to cause foodborne illness, as the page currently implies. RickScott (talk) 15:35, 19 April 2020 (UTC)[reply]

Your first link is to a website, not a published academic review, and the second link does not work for me.

Bottom line is that there is a book quote saying it does, as well as the Review paper used as a source in the article.

Anecdotally, if it helps, I have experienced symptoms from rice flapjack cooked at low temperatures, so I personally have no doubt that spores can turn into vegetative forms & cause problems.

There lots more published evidence too, as you could have found with a cursory search:

Human intake of members of the B. cereus group can therefore either be deliberately intended, as is the case for probiotics, or nonintended through ingestion of food contaminated with residues of commercially applied or naturally occurring strains. In both cases, the cells are primarily ingested as spores. In food poisoning cases caused by B. cereus spores, the strains are believed to adhere to mucosal epithelium of the small intestine, and thereafter to germinate. The resulting vegetative cells produce enterotoxins responsible for diarrhoeal symptoms (Granum & Lund, 1997).

[5]

The mechanism of the diarrhoeal syndrome is believed to be as follows: food contaminated with B. cereus spores and/or vegetative cells is consumed. Spores pass through the stomach, reach the small intestine, germinate, grow, and thereby produce enterotoxins. Vegetative cells are believed to be very susceptible to stomach conditions, and will therefore hardly reach the small intestine

[6] (You'll have to google to get the full text).

Please stop now. This issue is not in dispute. Ratel 🌼 (talk) 00:08, 20 April 2020 (UTC)[reply]

Wiki Education assignment: MIBO 3500 Introduction to Microbiology[edit]

This article was the subject of a Wiki Education Foundation-supported course assignment, between 18 August 2022 and 5 December 2022. Further details are available on the course page. Student editor(s): Is73500, Anonymous microbe, Danimahoney, Jmoyang58 (article contribs). Peer reviewers: Aetilghman, Eecc27, Meghanherlitzka, Ragi02, Chinedu23, Nathalieslebreton, REL9040, Egross123, Bab35555, Dmancao7, Asherkhan5284.

— Assignment last updated by ICapt.NemoI (talk) 19:23, 19 October 2022 (UTC)[reply]