Escherichia coli O157:H7
Overview
 
Escherichia coli O157:H7 is an enterohemorrhagic
Enterohemorrhagic
Enterohemorrhagic microorganisms are those that, as part of their pathogenesis, cause bloody diarrhea and colitis. While many pathogens are enterohemorrhagic, most cases observed are derived of E. coli serotype O157:H7. The E. coli O104:H4 strain identified as the cause of the 2011 outbreak in...

 strain of the bacterium
Bacteria
Bacteria are a large domain of prokaryotic microorganisms. Typically a few micrometres in length, bacteria have a wide range of shapes, ranging from spheres to rods and spirals...

 Escherichia coli
Escherichia coli
Escherichia coli is a Gram-negative, rod-shaped bacterium that is commonly found in the lower intestine of warm-blooded organisms . Most E. coli strains are harmless, but some serotypes can cause serious food poisoning in humans, and are occasionally responsible for product recalls...

 and a cause of foodborne illness
Foodborne illness
Foodborne illness is any illness resulting from the consumption of contaminated food, pathogenic bacteria, viruses, or parasites that contaminate food, as well as chemical or natural toxins such as poisonous mushrooms.-Causes:Foodborne illness usually arises from improper handling, preparation, or...

. Infection often leads to hemorrhagic diarrhea
Diarrhea
Diarrhea , also spelled diarrhoea, is the condition of having three or more loose or liquid bowel movements per day. It is a common cause of death in developing countries and the second most common cause of infant deaths worldwide. The loss of fluids through diarrhea can cause dehydration and...

, and occasionally to kidney
Kidney
The kidneys, organs with several functions, serve essential regulatory roles in most animals, including vertebrates and some invertebrates. They are essential in the urinary system and also serve homeostatic functions such as the regulation of electrolytes, maintenance of acid–base balance, and...

 failure, especially in young child
Child
Biologically, a child is generally a human between the stages of birth and puberty. Some vernacular definitions of a child include the fetus, as being an unborn child. The legal definition of "child" generally refers to a minor, otherwise known as a person younger than the age of majority...

ren and elderly persons. Transmission is via the fecal-oral route
Fecal-oral route
The fecal-oral route, or alternatively, the oral-fecal route or orofecal route is a route of transmission of diseases, in which they are passed when pathogens in fecal particles from one host are introduced into the oral cavity of another potential host.There are usually intermediate steps,...

, and most illness has been associated with eating undercooked, contaminated ground beef
Ground beef
Beef mince, ground beef, hamburger meat , hamburg or minced meat is a minced meat food, made of beef finely chopped by a mincer. It is used in many recipes including hamburgers and cottage pie...

, swimming in or drinking contaminated water, and eating contaminated vegetables.
E. coli serotype
Serotype
Serotype or serovar refers to distinct variations within a subspecies of bacteria or viruses. These microorganisms, viruses, or cells are classified together based on their cell surface antigens...

 O157:H7 is a Gram-negative
Gram-negative
Gram-negative bacteria are bacteria that do not retain crystal violet dye in the Gram staining protocol. In a Gram stain test, a counterstain is added after the crystal violet, coloring all Gram-negative bacteria with a red or pink color...

, rod-shaped bacterium.
Encyclopedia
Escherichia coli O157:H7 is an enterohemorrhagic
Enterohemorrhagic
Enterohemorrhagic microorganisms are those that, as part of their pathogenesis, cause bloody diarrhea and colitis. While many pathogens are enterohemorrhagic, most cases observed are derived of E. coli serotype O157:H7. The E. coli O104:H4 strain identified as the cause of the 2011 outbreak in...

 strain of the bacterium
Bacteria
Bacteria are a large domain of prokaryotic microorganisms. Typically a few micrometres in length, bacteria have a wide range of shapes, ranging from spheres to rods and spirals...

 Escherichia coli
Escherichia coli
Escherichia coli is a Gram-negative, rod-shaped bacterium that is commonly found in the lower intestine of warm-blooded organisms . Most E. coli strains are harmless, but some serotypes can cause serious food poisoning in humans, and are occasionally responsible for product recalls...

 and a cause of foodborne illness
Foodborne illness
Foodborne illness is any illness resulting from the consumption of contaminated food, pathogenic bacteria, viruses, or parasites that contaminate food, as well as chemical or natural toxins such as poisonous mushrooms.-Causes:Foodborne illness usually arises from improper handling, preparation, or...

. Infection often leads to hemorrhagic diarrhea
Diarrhea
Diarrhea , also spelled diarrhoea, is the condition of having three or more loose or liquid bowel movements per day. It is a common cause of death in developing countries and the second most common cause of infant deaths worldwide. The loss of fluids through diarrhea can cause dehydration and...

, and occasionally to kidney
Kidney
The kidneys, organs with several functions, serve essential regulatory roles in most animals, including vertebrates and some invertebrates. They are essential in the urinary system and also serve homeostatic functions such as the regulation of electrolytes, maintenance of acid–base balance, and...

 failure, especially in young child
Child
Biologically, a child is generally a human between the stages of birth and puberty. Some vernacular definitions of a child include the fetus, as being an unborn child. The legal definition of "child" generally refers to a minor, otherwise known as a person younger than the age of majority...

ren and elderly persons. Transmission is via the fecal-oral route
Fecal-oral route
The fecal-oral route, or alternatively, the oral-fecal route or orofecal route is a route of transmission of diseases, in which they are passed when pathogens in fecal particles from one host are introduced into the oral cavity of another potential host.There are usually intermediate steps,...

, and most illness has been associated with eating undercooked, contaminated ground beef
Ground beef
Beef mince, ground beef, hamburger meat , hamburg or minced meat is a minced meat food, made of beef finely chopped by a mincer. It is used in many recipes including hamburgers and cottage pie...

, swimming in or drinking contaminated water, and eating contaminated vegetables.

Bacteriology

E. coli serotype
Serotype
Serotype or serovar refers to distinct variations within a subspecies of bacteria or viruses. These microorganisms, viruses, or cells are classified together based on their cell surface antigens...

 O157:H7 is a Gram-negative
Gram-negative
Gram-negative bacteria are bacteria that do not retain crystal violet dye in the Gram staining protocol. In a Gram stain test, a counterstain is added after the crystal violet, coloring all Gram-negative bacteria with a red or pink color...

, rod-shaped bacterium. The "O" in the name refers to the cell wall (somatic
Somatic antigen
A somatic antigen is an antigen located in the cell wall of a gram-positive or gram-negative bacterium....

) antigen number, whereas the "H" refers to the flagella
Flagellum
A flagellum is a tail-like projection that protrudes from the cell body of certain prokaryotic and eukaryotic cells, and plays the dual role of locomotion and sense organ, being sensitive to chemicals and temperatures outside the cell. There are some notable differences between prokaryotic and...

 antigen. Other serotypes may cause (usually less severe) illness, but only those with the specific O157:H7 combination are reviewed here. Other bacteria may be classified by "K" or capsular antigens. (The "O" stands for [Ger. "without huff" or "without film"]; "H" for Hauch; and "K" for .) This is one of hundreds of serotypes of the bacterium Escherichia coli
Escherichia coli
Escherichia coli is a Gram-negative, rod-shaped bacterium that is commonly found in the lower intestine of warm-blooded organisms . Most E. coli strains are harmless, but some serotypes can cause serious food poisoning in humans, and are occasionally responsible for product recalls...

. While most strains are harmless and normally found in the intestines of mammals, this strain may produce shiga-like toxin
Shiga-like toxin
Shiga-like toxin, also known as verotoxin, is a toxin generated by some strains of Escherichia coli . It is named for its similarity to the AB5-type Shiga toxin produced by the bacteria Shigella dysenteriae....

s and cause severe illness, and is a member of a class of pathogenic E. coli known as enterohemorrhagic Escherichia coli or EHEC. Often they are referred to by their toxin producing capabilities, verocytotoxin producing E. coli (VTEC) or Shiga-like toxin producing E. coli (STEC).

E. coli O157:H7 was first recognized as a pathogen as a result of an outbreak of unusual gastrointestinal illness in 1982. The outbreak was traced to contaminated hamburger
Hamburger
A hamburger is a sandwich consisting of a cooked patty of ground meat usually placed inside a sliced bread roll...

s, and the illness was similar to other incidents in the United States and Japan. The etiologic agent of the illness was identified as a rare O157:H7 serotype of E. coli in 1983. This serotype had only been isolated once before, from a sick patient in 1975.

E. coli O157:H7 is markedly different from other pathogenic E. coli, as well. In particular, the O157:H7 serotype is negative for invasiveness (Sereny test
Sereny test
The Sereny test is a test used to test the invasiveness of organisms such as Escherichia coli.It is also used on Listeria monocytogenes.It is done by inoculating suspension of bacteria into guinea pig's eye...

), adheres through the E. coli common pilus (ECP), and does not produce heat stable or heat labile toxins. In addition, E. coli O157:H7 is usually sorbitol
Sorbitol
Sorbitol, also known as glucitol, Sorbogem® and Sorbo®, is a sugar alcohol that the human body metabolizes slowly. It can be obtained by reduction of glucose, changing the aldehyde group to a hydroxyl group. Sorbitol is found in apples, pears, peaches, and prunes...

 negative, whereas 93% of all E. coli ferment sorbitol. E. coli O157:H7 also lacks the ability to hydrolyze 4-methylumbelliferyl-β-D-glucuronide (MUG) and does not grow at 45 °C in the presence of 0.15% bile salts. Because of the latter characteristic, this serotype cannot be isolated by using standard fecal coliform methods that include incubation at 45 °C.

E. coli O157:H7 serotypes are closely related, descended from a common ancestor, divergent in plasmid
Plasmid
In microbiology and genetics, a plasmid is a DNA molecule that is separate from, and can replicate independently of, the chromosomal DNA. They are double-stranded and, in many cases, circular...

 content more than chromosomal content, and are no more related to other shiga toxin
Shiga toxin
Shiga toxins are a family of related toxins with two major groups, Stx1 and Stx2, whose genes are considered to be part of the genome of lambdoid prophages. The toxins are named for Kiyoshi Shiga, who first described the bacterial origin of dysentery caused by Shigella dysenteriae. The most common...

 producing strains than any other randomly chosen E. coli serotype. E. coli O55:H7 and E. coli O157:H7 are most closely related and diverged from a common pathogenic ancestor that possessed the ability to form attaching and effacing lesions. E. coli O157:H7 serotypes apparently arose as a result of horizontal gene transfer
Horizontal gene transfer
Horizontal gene transfer , also lateral gene transfer , is any process in which an organism incorporates genetic material from another organism without being the offspring of that organism...

 of virulence factors.

Among these virulence factors are a periplasmic catalase and shiga-like toxins
Shiga toxin
Shiga toxins are a family of related toxins with two major groups, Stx1 and Stx2, whose genes are considered to be part of the genome of lambdoid prophages. The toxins are named for Kiyoshi Shiga, who first described the bacterial origin of dysentery caused by Shigella dysenteriae. The most common...

. Shiga-like toxins are iron-regulated toxins that catalytically inactivate 60S
60S
60S is the large ribosomal subunit in eukaryotes. It corresponds to 50S in prokaryotes.It consists of the following:* 5S* 28S* 5.8SThe following is a list of proteins contained within the 60S ribosome:...

 ribosomal subunits of eukaryotic cells, blocking mRNA translation and causing cell death.
Shiga-like toxins are functionally identical to toxins produced by virulent Shigella
Shigella
Shigella is a genus of Gram-negative, nonspore forming, non-motile, rod-shaped bacteria closely related to Escherichia coli and Salmonella. The causative agent of human shigellosis, Shigella causes disease in primates, but not in other mammals. It is only naturally found in humans and apes. During...

 species.
Strains of E. coli that express shiga-like toxins gained this ability due to infection with a prophage
Transduction (genetics)
Transduction is the process by which DNA is transferred from one bacterium to another by a virus. It also refers to the process whereby foreign DNA is introduced into another cell via a viral vector. Transduction does not require cell-to-cell contact , and it is DNAase resistant...

 containing the structural coding for the toxin, and nonproducing strains may become infected and produce shiga-like toxins after incubation with shiga toxin positive strains. The prophage
Prophage
A prophage is a phage genome inserted and integrated into the circular bacterial DNA chromosome. A prophage, also known as a temperate phage, is any virus in the lysogenic cycle; it is integrated into the host chromosome or exists as an extrachromosomal plasmid. Technically, a virus may be called...

 responsible seems to have infected the strain's ancestors fairly recently, as viral particles have been observed to replicate in the host if it is stressed in some way (e.g. antibiotics).
The periplasmic catalase is encoded on the pO157 plasmid, and is believed to be involved in virulence by providing additional oxidative protection when infecting the host.

Natural Habitat

While relatively uncommon, E. coli O157:H7 can naturally be found in the intestinal contents of some cattle. Because ruminants lack a receptor for the toxin the bacteria produce, it does not cause disease in them and is considered commensal
Commensalism
In ecology, commensalism is a class of relationship between two organisms where one organism benefits but the other is neutral...

.

Transmission

Infection with E. coli O157:H7 follows ingestion of contaminated food or water, or oral contact with contaminated surfaces. It is highly virulent
Virulence
Virulence is by MeSH definition the degree of pathogenicity within a group or species of parasites as indicated by case fatality rates and/or the ability of the organism to invade the tissues of the host. The pathogenicity of an organism - its ability to cause disease - is determined by its...

, with a low infectious dose
Infectious dose
Infectious dose is the amount of pathogen required to cause an infection in the host.Usually it varies according to the pathogenic agent and the consumer's age and overall health....

: an inoculation of fewer than 10 to 100 CFU
Colony-forming unit
In microbiology, colony-forming unit is a measure of viable bacterial or fungal numbers. Unlike direct microscopic counts where all cells, dead and living, are counted, CFU measures viable cells...

 of E. coli O157:H7 is sufficient to cause infection, compared to over one-million CFU for other pathogenic E. coli strains.

A main source of infection is undercooked ground beef; other sources include consumption of unpasteurized milk and juice, raw produce and salami
Salami
Salami is cured sausage, fermented and air-dried meat, originating from one of a variety of animals. Historically, salami has been popular among Southern European peasants because it can be stored at room temperature for periods of up to 10 years, supplementing a possibly meager or inconsistent...

, and contact with infected live animals.
Waterborne transmission occurs through swimming in contaminated lakes, pools, or drinking inadequately treated water. The organism is easily transmitted from person to person and has been difficult to control in child day-care centers.

E. coli O157:H7 is found on cattle farms and can live in the intestines of healthy cattle. The toxin requires highly specific receptor
Receptor (biochemistry)
In biochemistry, a receptor is a molecule found on the surface of a cell, which receives specific chemical signals from neighbouring cells or the wider environment within an organism...

s on the cells' surface in order to attach and enter the cell; species such as cattle
Cattle
Cattle are the most common type of large domesticated ungulates. They are a prominent modern member of the subfamily Bovinae, are the most widespread species of the genus Bos, and are most commonly classified collectively as Bos primigenius...

, swine, and deer
Deer
Deer are the ruminant mammals forming the family Cervidae. Species in the Cervidae family include white-tailed deer, elk, moose, red deer, reindeer, fallow deer, roe deer and chital. Male deer of all species and female reindeer grow and shed new antlers each year...

 which do not carry these receptors may harbor toxigenic bacteria without any ill effect, shedding them in their feces, from which they may be spread to humans. Flesh can become contaminated during slaughter and butchering, and organisms can be thoroughly mixed into beef when it is ground into hamburger. Bacteria present on the cow's udder
Udder
An udder is an organ formed of the mammary glands of female quadruped mammals, especially ruminants such as cattle, goats, sheep and deer. The udder is a single mass hanging beneath the animal, consisting of pairs of mammary glands...

s or on equipment may get into raw milk. Contaminated foods look, smell, and taste the same as their normal counterparts.

Another potential vector of E. coli O157:H7 is filth flies (which includes house flies, Musca domestica). Filth flies have been shown to be vectors of E. coli O157:H7 using PCR
Polymerase chain reaction
The polymerase chain reaction is a scientific technique in molecular biology to amplify a single or a few copies of a piece of DNA across several orders of magnitude, generating thousands to millions of copies of a particular DNA sequence....

.

United States food advocates have unsuccessfully attempted to control the spread of this illness by promoting the so-called "Kevin's Law
Kevin's law
Kevin's Law was proposed legislation that would have given the U.S...

". This law would give the United States Department of Agriculture power to shut down food processing plants that fail multiple inspections. The food processing industry vigorously opposes this proposal.

Signs and symptoms

E. coli O157:H7 infection often causes severe, acute hemorrhagic diarrhea (although nonhemorrhagic diarrhea is also possible) and abdominal cramp
Cramp
Cramps are unpleasant, often painful sensations caused by muscle contraction or over shortening. Common causes of skeletal muscle cramps include muscle fatigue, low sodium, and low potassium...

s. Usually little or no fever is present, and the illness resolves in five to 10 days. It can also be asymptomatic
Asymptomatic
In medicine, a disease is considered asymptomatic if a patient is a carrier for a disease or infection but experiences no symptoms. A condition might be asymptomatic if it fails to show the noticeable symptoms with which it is usually associated. Asymptomatic infections are also called subclinical...

.

In some people, particularly children under five years of age and the elderly, the infection can cause hemolytic uremic syndrome (HUS), in which the red blood cell
Red blood cell
Red blood cells are the most common type of blood cell and the vertebrate organism's principal means of delivering oxygen to the body tissues via the blood flow through the circulatory system...

s are destroyed and the kidneys fail. About 2–7% of infections lead to this complication. In the United States, HUS is the principal cause of acute kidney failure in children, and most cases of HUS are caused by E. coli O157:H7.

Diagnosis

A stool culture
Stool test
A stool test is one where fecal matter is collected for analysis to diagnose the presence or absence of a medical condition.-Fecal occult blood test:...

 can detect the bacterium, although it is not a routine test and so must be specifically requested. The sample is cultured on sorbitol-MacConkey
Sorbitol-MacConkey agar
Sorbitol MacConkey agar is a variant of traditional MacConkey agar used in the detection of E. coli O157:H7. Traditionally, MacConkey agar has been used to distinguish those bacteria that ferment lactose from those that do not...

 (SMAC) agar
Agar
Agar or agar-agar is a gelatinous substance derived from a polysaccharide that accumulates in the cell walls of agarophyte red algae. Throughout history into modern times, agar has been chiefly used as an ingredient in desserts throughout Asia and also as a solid substrate to contain culture medium...

, or the variant cefixime potassium tellurite sorbitol-MacConkey agar (CT-SMAC). On SMAC agar O157 colonies appear clear due to their inability to ferment sorbitol, while the colonies of the usual sorbitol-fermenting serotypes of E. coli appear red. Sorbitol nonfermenting colonies are tested for the somatic O157 antigen before being confirmed as E. coli O157. Like all cultures, diagnosis is time-consuming with this method; swifter diagnosis is possible using PCR
Polymerase chain reaction
The polymerase chain reaction is a scientific technique in molecular biology to amplify a single or a few copies of a piece of DNA across several orders of magnitude, generating thousands to millions of copies of a particular DNA sequence....

 techniques. Newer technologies using fluorescent and antibody
Antibody
An antibody, also known as an immunoglobulin, is a large Y-shaped protein used by the immune system to identify and neutralize foreign objects such as bacteria and viruses. The antibody recognizes a unique part of the foreign target, termed an antigen...

 detection are also under development.

Surveillance

E. coli O157:H7 infection is nationally reportable in the USA and Great Britain, and is reportable in most US states.

Treatment

While fluid replacement and blood pressure support may be necessary to prevent death from dehydration, most victims recover without treatment in five to 10 days. There is no evidence that antibiotics improve the course of disease, and treatment with antibiotic
Antibiotic
An antibacterial is a compound or substance that kills or slows down the growth of bacteria.The term is often used synonymously with the term antibiotic; today, however, with increased knowledge of the causative agents of various infectious diseases, antibiotic has come to denote a broader range of...

s may precipitate kidney complications. Antidiarrheal agents, such as loperamide
Loperamide
Loperamide , a synthetic piperidine derivative, is an opioid drug used against diarrhea resulting from gastroenteritis or inflammatory bowel disease. In most countries it is available generically and under brand names such as Lopex, Imodium, Dimor, Fortasec, and Pepto Diarrhea Control...

 (imodium), should also be avoided.

Hemolytic-uremic syndrome
Hemolytic-uremic syndrome
Hemolytic-uremic syndrome , abbreviated HUS, is a disease characterized by hemolytic anemia, acute renal failure and a low platelet count . It predominantly, but not exclusively, affects children. Most cases are preceded by an episode of diarrhea caused by E. coli O157:H7, which is acquired as a...

 is a life-threatening condition usually treated in an intensive care unit
Intensive Care Unit
thumb|220px|ICU roomAn intensive-care unit , critical-care unit , intensive-therapy unit/intensive-treatment unit is a specialized department in a hospital that provides intensive-care medicine...

. Blood transfusion
Blood transfusion
Blood transfusion is the process of receiving blood products into one's circulation intravenously. Transfusions are used in a variety of medical conditions to replace lost components of the blood...

s and kidney dialysis are often required. With intensive care, the death rate for hemolytic uremic syndrome is 3–5%.

Costs

The pathogen results in an estimated 2,100 hospitalizations annually in the United States. The illness is often misdiagnosed; therefore, expensive and invasive diagnostic procedures may be performed. Patients who develop HUS often require prolonged hospitalization, dialysis, and long-term followup.

Agricultural

Beef processing is a common point of contamination: during the slaughtering process, the contents of intestines or fecal material on the hide could mix with the meat, thus allowing bacteria to flourish in the warm, damp conditions. If the infected parts are then ground, the bacteria go from the surface of the cut to the interior of the ground mass. Ground beef is therefore much more likely to be a source of infection than steak. In steak, only the surface area of a cut is exposed during butchering, and cooking the outside affects the entire exposed portion. In ground beef, however, bacteria are mixed throughout the meat mass, requiring the entire mass to be heated thoroughly to eliminate the pathogen. Additionally, in the production of ground beef, meat from multiple cattle is often ground together, enabling contamination from a single animal to contaminate an entire lot of ground beef.

Accordingly, reduction of infection requires preventive measures that either reduce the number of cattle that carry E. coli O157:H7 or reduce the contamination of meat during slaughter and grinding. These measures include careful removal and cleaning of the intestines, steam/vacuum treatment, and organic acid sprays.

In January 2007, Canadian biopharmaceutical company Bioniche announced it had developed a bovine vaccine capable of reducing O157:H7 in cattle by over 99%.

On March 4, 2009, the United States Department of Agriculture (USDA) granted Epitopix a conditional license for the first E. coli O157 vaccine for cattle in the U.S.

In May 2010, a paper from the University of Texas Southwestern Medical Center detailed preliminary results of research into the sensing mechanisms used by O157:H7 to determine when to adopt an acid-resistant state needed to escape from the digestive tract. The study introduced two different strains of E. coli lacking normal sensing mechanisms into the rumens of grain-fed cattle. The strains were unable to pass through the stomach. Next, the researchers plan to conduct tests on grass-fed cattle to establish if the mechanism is the same.

Culinary and dietary

Cooking all ground beef
Ground beef
Beef mince, ground beef, hamburger meat , hamburg or minced meat is a minced meat food, made of beef finely chopped by a mincer. It is used in many recipes including hamburgers and cottage pie...

 and hamburger
Hamburger
A hamburger is a sandwich consisting of a cooked patty of ground meat usually placed inside a sliced bread roll...

s thoroughly, and checking the temperature using an instant-read meat thermometer
Thermometer
Developed during the 16th and 17th centuries, a thermometer is a device that measures temperature or temperature gradient using a variety of different principles. A thermometer has two important elements: the temperature sensor Developed during the 16th and 17th centuries, a thermometer (from the...

, will eliminate the organism. Ground beef should be cooked until a thermometer inserted into several parts of the patty, including the thickest part, reads at least 72 °C (161.6 °F).

When preparing meat, it should be kept separate from other food items and all surfaces, and utensils which come into contact with raw meat should be washed thoroughly before being used again. Hand washing
Hand washing
Hand washing for hand hygiene is the act of cleaning the hands with or without the use of water or another liquid, or with the use of soap, for the purpose of removing soil, dirt, and/or microorganisms....

 is similarly important. Placing cooked hamburgers or ground beef on an unwashed plate that held raw patties can transmit infection. This was the main cause of the E. coli poisoning in Scotland in 1996 that killed seven and left hundreds infected.

Unpasteurized milk and juices are potential sources of E. coli. Commercial juice is almost always pasteurized, and juice concentrates are also heated sufficiently to kill pathogen
Pathogen
A pathogen gignomai "I give birth to") or infectious agent — colloquially, a germ — is a microbe or microorganism such as a virus, bacterium, prion, or fungus that causes disease in its animal or plant host...

s.

Fruits and vegetables should be washed thoroughly, especially those that will not be cooked. Children under five years of age, immunocompromised persons, and the elderly should avoid eating alfalfa
Alfalfa
Alfalfa is a flowering plant in the pea family Fabaceae cultivated as an important forage crop in the US, Canada, Argentina, France, Australia, the Middle East, South Africa, and many other countries. It is known as lucerne in the UK, France, Australia, South Africa and New Zealand, and known as...

 sprouts until their safety can be assured. Methods to decontaminate alfalfa seed
Seed
A seed is a small embryonic plant enclosed in a covering called the seed coat, usually with some stored food. It is the product of the ripened ovule of gymnosperm and angiosperm plants which occurs after fertilization and some growth within the mother plant...

s and sprout
Sprout
Sprout may refer to:* Shoot, the early growth of a plant** Edible sprouts* Sprouting, germination of seed* Brussels sprout, a green vegetable* Sprouts , a pencil-and-paper game...

s are being investigated.

Before consumption, contaminated water should be sterilized by 1) boiling at a rolling boil for at least one minute (longer at higher altitudes), 2) ultrafiltration using a system designed for water treatment, or 3) chemically sterilized using an ozone, chlorine, or iodine product. Care while swimming to avoid ingestion of potentially contaminated water can reduce the chances of infection.

Proper hand washing
Hand washing
Hand washing for hand hygiene is the act of cleaning the hands with or without the use of water or another liquid, or with the use of soap, for the purpose of removing soil, dirt, and/or microorganisms....

 after using the lavatory or changing a diaper, especially among children or those with diarrhea, reduces the risk of transmission. Anyone with a diarrheal illness should avoid swimming in public pools or lakes, sharing baths with others, and preparing food for others.

United States

The U.S.D.A. banned the sale of ground beef contaiminated with the O157:H7 strain in 1994.

See also

  • 2011 E. coli O104:H4 outbreak
  • Centers for Disease Control and Prevention
    Centers for Disease Control and Prevention
    The Centers for Disease Control and Prevention are a United States federal agency under the Department of Health and Human Services headquartered in Druid Hills, unincorporated DeKalb County, Georgia, in Greater Atlanta...

  • Escherichia coli O104:H4
    Escherichia coli O104:H4
    Escherichia coli O104:H4 is a rare enterohemorrhagic strain of the bacterium Escherichia coli, and the cause of the 2011 Escherichia coli O104:H4 outbreak...

  • Escherichia coli O121
    Escherichia coli O121
    Escherichia coli O121 is a serotype of Escherichia coli, a species of bacteria that lives in the lower intestines of mammals. The presence of many serotypes of E. coli in animals is beneficial or does not cause disease. However, E. coli O121 has been recognized as a potential disease causing...

  • Food-induced purpura
    Food-induced purpura
    Food-induced purpura is a skin condition that may result from ingestion of tartrazine dye, benzoates, and food containing Escherichia coli O157:H7....

  • List of foodborne illness outbreaks

External links

The source of this article is wikipedia, the free encyclopedia.  The text of this article is licensed under the GFDL.
 
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