Contents
Introduction
History
Characteristics
Mechanism of action
Factors affects growth
Toxins
Symptoms
Transmission
Complications
Outbreaks
Food Association
Diagnosis
Disinfetants
Trearment
Vaccination
Preventions
References
Enterohemorrhagic Escherichia coli
Introduction
E.coli is a gram negative bacteria present in the form of rods(bacillus) in the Enterobacteriaceae. Mostly E.coli are normal commensals of intestines so that isolation of pathogenic strains on the basis of Virulence factors e.g toxins. EHEC group produces shiga-like toxins (stx), enterohemolysin, and intimate adhesion factor (Intimin).
Serotypes
E.coli serotypes based on the antigens as O (somatic polysaccharides), H (flagellar) and K (capsular). EHEC serotypes comprises of E.coli O157:H7 and others O26, O103, O111, O145. Resarch studies shows only small no. of E.coli are enough to cause infection as 10-100 microbes.
History of EHEC
In 1982,E.coli O157:H7 was first identified to cause bloody diarrhea by eating undercooked or contaminated raw hamburger.
Infection was first recognized by CDC separates two outbreaks in Oregon and Michigan by eating hamburger at National chain restaurants.
Patients experienced hemorrhagic colitis (Inflammation and bleeding of colon) due to E.coli O157:H7 referred as hamburger disease.
Characteristics
• E.coli O157:H7 is a principal serotype associated with hemorrhagic colitis
• It does not ferment sorbitol and have glucuronidase activity when comparing with other E.coli strains.
• It grows rapidly at 30-42°C, poor growth at 44-45°C, and shows no growth at 10°C.
• It is resistant to pH 4.5...
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FUNDAMENTAL
FOOD MICROBIOLOGY FOURTH EDITION
During the investigation, seven test were used to determine the unknown bacterium as Salmonella typhimurium. “Salmonella typhimurium is a genus of gram-negative, non-lactose fermenting, medium-sized, rod-shaped, bacteria, members of the family Enterobacteriaceae, most species having flagella and pili” (medical-dictionary). This bacterium is known for causing food poisoning. This illnesses usually last 4-7 days. Treatments for the illnesses caused by this bacterium are dependent upon the severity of the symptoms, the age of the patient, and the comorbidities.
Johnson, J., & Russo, T. (2002). Extraintestinal pathogenic Escherichia coli : “The other bad E coli ”. Journal of Laboratory and Clinical Medicine, 139(3), 155-162.
We observed the agar plate for colonies that had a metallic look, because these were likely E.coli colonies. We then recorded what we saw. After selecting what we believed to be an E. coli coliform colony, we inoculated a TSA slant, in addition to another lactose broth, and incubated these for another 24 hours at 37°C.
“Salmonella Questions and Answers.” USDA Food Safety and Inspection Service. 20 Sept. 2006. 20 July 2008 .
Eric Schlosser of “Fast Food Nation” exploits the negative changes it causes. In “Fast Food Nation” Eric Schlosser takes parts to talk about how fast food changed the way animal were raised in order to meet demands from the people. He exploited larger proportion of fast food is made from sub-standard meats, which are taken from low quality animals. In short, the meat is not from one common placed, but rather from a host of parts that are pounded together to make a whole burger. To which a single disease like E.coli can spread to multiple meat products. “E. coli 0157:H7 is a mutated version of a bacterium found abundantly in the human digestive system. Most E. coli bacteria help us digest food, synthesize vitamins, and guard against dangerous organisms. E. coli 0157:H7, on the other hand, can release a powerful toxin- called a "Vero toxin" or a "Shiga toxin"-that attacks the lining of the intestine….A single animal infected with E. coli 0157:H7 can contaminate 32,000 pounds of that ground beef” (Schlosser). The likelihood of disease spread is very high since the meat is taken from different animals. In chapter 9 of the book, he provides a case in which ground meat was recalled after E. coli was identified. The worst part of that, was that 25 million pounds of the meat had been consumed. He also warns that with fast foods, the possibility of nationwide food
Kapper, J.B. Nataro, J.P. & Mobley, H.L.T. 2004, "PATHOGENIC ESCHERICHIA COLI", Nature Reviews, vol. 2, pp. 123-140.
Over the past few years there has been several cases of food contaminated with Escherichia Coli and Salmonella, mostly from organic food manufacturers. For a better understanding of this issue it is necessary to go back to the basis for organic agriculture. Which is essentially about the nutrients needed for the soil and its direct relation to the quality of the product. The more nutrients are added to the substrate the better the quality of that product. Farmers replace synthetic fertilizers and chemical pesticides for natural alternate methods, using fertilizers based on decomposed organic matter like Humus and Compost. Among the active components found in this products are animal feces which contain harmful parasites that could be transmitted to the plants. Several studies support this statement; an evaluation from the University of Minnesota revealed that “the percentages of E.coli–positive samples in conventional and organic produce (on farms in Minnesota), were 1.6 and 9.7%, respectively” (Mukherjee, Speh, Dyck, Diez-Gonzalez,
E. coli, short for Escherichia coli, normally live within the digestive system of humans and animals. Most variants of this bacteria are mostly benign and are actually essential for digestive health in people and animals. But there is the more infamous and most dangerous strain of E. coli, notorious for poisoning people and causing serious symptoms and even death. It has been labelled as E. coli O157:H7, discovered in 1982. This specific strain produces a toxin with the name Shiga that causes symptoms such as kidney failure, bloody diarrhea, and death. There have been outbreaks of O157:H7 in the US, Canada, Europe, South Africa, and Eastern Asia. These types of E. coli are labelled as pathogenic, meaning they can spread and cause illness outside
E. Coli 0157, written by Mary Heersink, is a nerve-racking, adrenaline-filled story of a mother's experience with a then unknown deadly bacteria. The book brings up many reactions in its readers, especially the questioning of the practice of doctors in hospitals. The reader's knowledge base of scientific procedures in emergency centers was widened as well as the knowledge of how to the human body reacts to different agents in its system.
E. coli may cause one of three different infections: urinary tract infection, neonatal meningitis, and or intestinal diseases. However, it most commonly causes intestinal disease. There are five classes of the bacteria that will cause this: enterotoxigenic E. coli, enteroinvasive E. coli, enterohemorrhagic E. coli, enteropathogenic E. coli and enteroaggregative E. coli. All five of these strains cause diarrhea. For
E. coli or Escherichia coli is a prokaryotic cell found the in lower digestive track of mammals and other warm blooded animals. E. coli is an easy bacteria to work with as it doubles quickly and is relatively easy to grow; millions of cells can be grown in several hours (Biotechnology Learning Hub 2014). E. coli is an ideal bacterium in the lab because it does not require its temperature to be too hot, too cold, or too precise (Biotechnology Learning Hub 2014). A general warm temperature is perfect for this bacterium. E. coli is also easy to care for it does not need a specific type of nutrient, in a lab setting it can be feed any agar, making the bacteria over all cheaper to care for. Strains of E. coli can also operate in aerobic or anaerobic environments (Koh et al. 2007).
coli when animals are being slaughtered or processed, even if precautions are taken. E.Coli can spread throughout the meat in the processing or grounding of meat, which can lead to high contamination levels throughout the plant.
Campylobacter is a bacterial pathogen that causes fever, diarrhea, and abdominal cramps. It is the commonly identified bacterial cause of diarrhea illness in the world. These bacteria live in the intestines of birds, and most raw poultry meat has the bacteria in it. Eating undercooked chicken or other food that has been contaminated with the juices dripping from raw chicken is the most frequent source of this particular infection.
Foodborne illness results from eating food contaminated with bacteria (or their toxins) or other pathogens such as parasites or viruses. The illnesses range from upset stomach to more serious symptoms, including diarrhea, fever, vomiting, abdominal cramps, and dehydration. Although most foodborne infections are undiagnosed and unreported, the Centers for Disease Control and Prevention estimates that every year about 76 million people in the United States become ill from pathogens in food. Of these, about 5,000 die.
There are two most common bacteria that cause food poisoning. Campylobacter and Salmonella are at the top of the list when food poisoning is discussed. These bacteria are primarily found in improperly cooked poultry, eggs, and unpasteurized juices or milks. When cooking, certain food items have to be cooked to the proper temperature