Talk:Escherichia coli O157:H7

From Wikipedia, the free encyclopedia

	This article is within the scope of WikiProject Medicine. Please visit the project page for details or ask questions at the doctor's mess.
B	This page has been rated as B-Class on the quality assessment scale
Mid	This article has been rated as Mid-importance on the importance assessment scale

	Biology Portal Escherichia coli O157:H7 is part of WikiProject Microbiology, which aims to improve Wikipedia's coverage of microbiology and microbiology-related topics. Please work to improve this article, or visit our project page to find other ways of helping.
B	This article has been rated as B-Class on the assessment scale.
Top	This article is on a subject of top-importance within microbiology.
Article Grading: The following comments were left by the quality and importance raters: (edit · refresh) The section on "Relationship to industrial agriculture" is likely biased. Certainly the information on the recent spinach out break should be trimmed and moved to a new section that covers notable outbreaks. The way the info is currently used is topical and inappropriate. The section as a whole tries to be neutral, but relys on sources that are biased or whose results are known to be contentious. It also important to realize there may be no relationship between industrial agriculture and EC O157:H7, and the section seem to ignore this possibility, at least doesn't present it fairly. One could go a long way towards a good article by deleting the whole section.James.folsom 23:19, 31 December 2006 (UTC)

[edit] Ground

Ground beef should be cooked until a thermometer inserted into several parts of the patty, including the thickest part, reads at least 160° F

People, please let's be serious and use some serious measures of temperature. How the f* should normal person know these 160° F ? Taw 22:10 May 9, 2003 (UTC)

It's 71.1 °C. I've rounded up in the article to be on the safe side :) -- Tarquin 22:16 May 9, 2003 (UTC)

I was going to round to 70° C, since the 160° F number looks rounded anyway, but an extra two degrees can't hurt. ;) -- John Owens 22:23 May 9, 2003 (UTC)

Anything above 155 Fahrenheit for over 30 seconds decimates populations of every known pathogenic bacterium. So rounding to 70 C is fine. --mav

Incorrect, spore forms are very resistant to heat, specificaly Bacillus...etc. I would side with saying "decimates vegetative forms of pathogenic bacterium."

Upon further study it looks like the 72 C figure is used all the time. In fact 72 C @ 15 seconds is fast pasteurization. Mind you this doesn't kill all bacteria but it does kill-off nearly every living pathogenic bacterium and most bacterial spores. --mav

Does anyone know how E.Coli contaminates produce? This article explains contamination in beef but not produce. Why are alfalfa sprouts so vulnerable?

From the FDA website: "According to the GAPs (good agricultural practices) guide, areas that should be considered to minimize the potential for the microbial contamination of produce include: agricultural water (e.g., for irrigation or crop protection sprays); wild and domestic animals; worker health and hygiene; the production environment (use of manure, previous land use, and use of adjacent land); post harvest water quality (water used to wash or cool produce) and sanitation of facilities and equipment."

The E. coli in the beef and the E. coli in the produce probably came from the same place; the cows digestive tract. The difference is that in the case of beef, the carcass was probably contaminated during slaughter when the gut was removed, whereas the produce was probably contaminated in the field when the cow used the bathroom somewhere nearby. —Preceding unsigned comment added by 128.163.170.152 (talk) 19:26, 3 March 2008 (UTC)

[edit] Name

There should be an explanation of why E. coli O157:H7 has such a long name. What do all those numbers mean?

See E. coli O157:H7#What is Escherichia coli O157:H7?, third paragraph. — [[User:Knowledge Seeker|Knowledge Seeker দ (talk)]] 17:26, 2 Dec 2004 (UTC)

[edit] Transmission

The transmission section looks like it was pulled directly from the CDC website. Can that be done?CDC --69.108.121.3 07:12, 16 September 2006 (UTC)

Hi, I moved your comment to the bottom as this is standard pratice in wikipedia, aides clarity (indeed the way you added your comment may have been confusing to people who didn't read the dates) and ensures your comment is likely to get an answer. Anyway as the article mentions at the bottom, two public domain sources are used for this article as linked to the CDC. The CDC is part of the US government and the page in question was the work of the CDCand therefore, as with all work of the United States Government it is not copyrighted but in the public domain. Hence, as with all material in the public domain we (and anyone else) can use it was we desire. Generally speaking, we do modify the work of time for consistency of style, language and to make it appropriate for a wikipedia article but there is obviously no copyright issue with using such work as is. Nil Einne 15:58, 30 September 2006 (UTC)

[edit] reportable?

In the "Surveillance" section, the word "reportable" looks to be used as a technical term. I'm guessing that it means it's mandatory to report to a health authority, although I could equally imagine it meaning that it's an optional report that they will accept. Perhaps somebody with more domain knowledge could expand or explain that bit? Thanks, William Pietri 10:41, 10 October 2006 (UTC)

[edit] industrial agriculture

A side effect of feeding grain to cattle is that it increases the acidity of their stomach - and it is in this acidic gut that the deadly O157:H7 thrives.

Where is the source for this statement? Stomachs generally have a pH of 2 or 3 and the e. coli lives in the bowels not the stomach.

Amen to that. The pH of the stomach is determined by the secretion of acid until it gets to the pH the body decides it wants, so I doubt that grain is involved. Secondly, E coli does not survive in MORE acidic environments, that would be more likely to sterilize the coli. And finally, just off the top of my head, if there were any effect of grain on coli production, and I wouldn't be surprised if there were, it would be because the rich feed leaves more nutrition in the residue in the large intestine for the coli to feed on. The same reason beans make you fart. As I said, that's just a guess on my part, but makes more sense than stomach acid involvement. Gzuckier 18:08, 26 November 2006 (UTC)

This section should be deleted, The concept that Industrial agriculture is responsible for the development of EC O157:H7 is not scientifically credible.James.folsom 23:25, 31 December 2006 (UTC)

Please don't delete anything just yet; but instead add lots of sourced data. Maybe what is going on is that the recent ability to track and analyse this kind of thing makes it look like this sort of thing is a recent phenomenon. If I had a source for that I would add it. But in any case let's add sourced data for now. Thanks. WAS 4.250 02:59, 1 January 2007 (UTC)

I deleted the following because it is based on an OP-ED peice in the new york times, that presents it as opinion with nothing backing it up. The article also contains many factual errors such as the statement that "(The bug can’t survive long in cattle living on grass.)", which is not true. As a microbiologist who is working with and has experiance working with EC O157:H7 I know of no evidence, nor would it be possible to have evidence that this organism evolved in cattle. And while it is true that EC O157:H7 is acid tolerant compared to other EC, it does not thrive in those conditions. At best it's a survival advantage, but Given that it is a human pathogen, not an animal pathogen, it is far more likely it's genesis occurred in human populations.James.folsom 18:52, 4 January 2007 (UTC)

"It is believed that this strain evolved in the digestive system of "grain fed" cattle on large industrial farms.^[1] On these farms, grain is used as cattle feed because it is nutrient-packed and increases efficiency. A side effect of feeding grain to cattle is that it increases the acidity of their stomach—and it is in this acidic gut that the deadly O157:H7 thrives."

I'm also moving this:

"There are several variants of E. coli and they can be found in a healthy human gut. The deadly strain, O157:H7 was first found in 1975, and the first outbreak was reported in 1982. ^[2] "

This info is partially a duplication of info in the biochemistry section, which has a better primary reference for all of this information. Both sections contained slight factual errors that I will have corrected.James.folsom 18:52, 4 January 2007 (UTC)

Still checking references and this passage is original research and I'm deleting it:

Another reason why the strain was not known before the 1980s was that only then did better technology became available to identify bacteria. http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=130684 As a single gram of rich, undisturbed soil may contain as many as 5,000 different species of bacteria (more bacterial species even than all those that have been described by science), it is not surprising that most of these have not been categorized yet.

The paper in the link does not discuss EC O157:H7, the paragraph is the authors opinion based on reading a paper on misidentification of bacteria.

I'm also removing this reference because the reference right before it, is a good review article that covers the whole topic, no need to back up such a paper with a OP-ED peice.

^[3]

James.folsom 21:49, 4 January 2007 (UTC)

Thank you James, it all looks much better! It is fine that you removed the piece about bacterial diversity, but do you not agree with the article that most bacteria have not been identified before the seventies and eighties of the 19th century?

Thanks, Nah, I had no problems with the article, I enjoyed skimming it, but to claim that this has anything to do with why there was so much difficulty in recognizing O157:H7 as a pathogen is just synthesis of original research. Technically speaking there was no problem recognizing the organism as e. coli, the problem was that it was negative for all the usual tests of e. coli pathogenicity and was causing sequalae that are usually the arena of shigella species. So A little head banging is to be expected.

I'm going to try and rewrite the section on cattle feeding controversy. The people who originally added that material actually used a pretty decent balanced review paper on the subject, so I'm going to just summarize that.

I also very much want to delete the last two paragraphs because they are really ideological in nature. I don't really disagree or agree with all these different ideologies of organic, little farmer, vs large industrial complex, vs government regulation vs no government regulation; but it's bit much to be arguing the points in this article. I'd like to see a separate article on all the different flavors of this ideology.

I will add though from talking with a reading material from people who are involved with this, that we'll see HAACP and regulations on green space and buffer zones around various farming types, and of course there are cattle vaccines that might help reduce the environmental incidence of O157. Plus it's my understanding that produce, especially lettuce is a market with very low profit margins, and irradiation may just be cost prohibitive. Really i've been thinking hard about this issue of O157:H7 and I've been forced to conclude that O157:H7 contamination may in fact be a fact of life. How do you keep bird feces out of a spinach field?James.folsom 21:03, 7 January 2007 (UTC)

Jee, you really put a lot of thought into this! Sorry, but I do not agree with the review article, it was highly subjective. The 1000-fold study was done on E.coli in general (not specifically this strain) as far as I can tell and the reverse was not done. Other articles reviewed in it seem to also lack proper diagnostics and statistics. I like the piece as you had it -> combining different opinions and studies without excluding either and writing it into one piece.

apparently that business about 1000 fold EC O157:H7 decrease has been propagandized so much by the various factions, that I didn't even notice that it wasn't accurate. I was going to fix it, but I kinda got disillusioned on the whole thing. In fact, in light of new studies coming out that show water contamination from humans is orders of magnitude higher than that of cattle, and just the fact that scientist can't agree on much about the topic; I want to delete the section, and probably will if I don't see a good argument for keeping it, soon.James.folsom 17:46, 11 January 2007 (UTC)

I'm deleting the Ag impact section, the code for the section follows so that if in the future a clear consensus develops, it may be reworked an added back.

==Relationship to industrial agriculture ==

Examople of a modern dairy farm where animals are sheltered in a structure providing food, water, ventilation, and specific resting spaces all designed to maximize production.

The 2006 United States E. coli outbreak is notable for bringing widespread attention to the link between wildlife and agriculture with the risk of E.coli produce contamination. This started with the discovery that this E. coli O157:H7 was found on a cattle ranch in the Salinas Valley that also rents land about a half-mile away to produce growers.^[4] In addition to being present in cattle fecal specimens, the E. coli O157:H7 samples were found in water from a creek and in the gastrointestinal tract of a wild boar present on the property. "Animals, wildlife and water were in close proximity to the field," Reilly said. "We have evidence for fences torn down, wildlife going into the actual spinach fields themselves. That's where the investigation is centered right now. There's clear evidence that the pig population has access and goes onto the fields.^[5][6]

In 2003, an article in the Journal of Dairy Science found that between 30 and 80 percent of cattle carry E. coli O157:H7. In that same journal article, a quick fix was pointed out: Cows that are switched from a "grain" diet to a forage diet saw, within 5 days, a 1,000-fold decrease in the abundance of E.coli.^[7] However, there is considerable debate on this point. Some studies, for example, indicate that the presence of the bacterium in the livestock is much lower than otherwise reported. A 2002 USDA NAHMS study found that 38.5% of dairy farms had at least one cow that was culture [+] when sampled, but only 4.3% of individual cows on these farms were shedding the organism. Indeed, several papers state the opposite of the Journal of Dairy Science, finding half as little of the strain in manure from animals fed by corn instead of barley.^[8][9][10]

More likely, rather than change the way cattle are fed or raised on industrial farms there will instead be pressure to find technological solutions like food irradiation, plans for HACCP, or simply cooking burgers longer. Suggestions like this have led some experts, like Professor of Science and Environmental Journalism at UC-Berkeley, Michael Pollan, to suggest that "All of these solutions treat E. coli O157:H7 as an unavoidable fact of life rather than what it is: a fact of industrial agriculture."^[11]

Advocates such as Howard Lyman and groups such as People for the Ethical Treatment of Animals have promoted vegetarianism in response to cases of E.coli infection.

[edit] Prevalence

"An estimated 73,000 cases of infection and 61 deaths occur each year in the United States alone,[2] although it is more common in less industrialized countries."

How can the disease have originated from the industrial farming if it is more present in less industrialized countries?

I'm slowly trying to deal with this, by rendering the industrial ag section NPOV. I was to eventually change the section heading, but I'm not sure what to chang it too. So ideas are welcome.James.folsom 21:04, 7 January 2007 (UTC)

It may just be a typo -> that it is less present in less industrialized countries, although I have not seen a study really examining this (going there with the same diagnostic tools and such).

I think it was a typo, I changed it because I found an abstract(http://www.current-reports.com/article.cfm?PubID=GR06-4-1-05&KeyWords=&Type=Abstract&CFID=10453305&CFTOKEN=38140760) claiming that it is more common in industrialized countries. I don't have online access to this article, so I don't know how valid the claim is. So I changed it and tagged it as needing a cite. I think this statement was added as circumstantial evidence for the industrial ag claims, anyway I doubt that there is any certainty on the matter.James.folsom 23:54, 7 January 2007 (UTC)

Sure, I'm getting curious about the article (couldn't open it either). Aren't most diseases first identified in industrialized countries (like AIDS/HIV)?

I'd venture to say yeah, it's matter of availibility of scientific resources, but don't forget about SARS, and ebola, and etc. Though it took western science to understand the diseases. There is some indication that O157:H7 was a problem in the US and Japan prior to 1982. I imagine it emerged in the US and spread to Japan via beef exports. Then spread out from there. But who knows really? I did notice that it seems to have arrived in brazil in 1990, and is a prblem in Nigeria.

[edit] Interesting take on the problem

An interesting take on the problem can be found here at this semi-reliable site. WAS 4.250 13:08, 22 January 2007 (UTC)