Escherichia coli (E. coli), is one of many species of bacteria living in the lower intestines of mammals, known as gut flora. When located in the large intestine, it assists with waste processing, vitamin K production, and food absorption.
E. coli are unable to sporulate Thus, treatments which kill all active bacteria, such as pasteurization or simple boiling, are effective for their eradication, without requiring the more rigorous sterilization which also deactivates spores.
As a result of their adaptation to mammalian intestines, E. coli grow best in vivo or at the higher temperatures characteristic of such an environment, rather than the cooler temperatures found in soil and other environments.
E. coli can generally cause several intestinal and extra-intestinal infections such as urinary tract infections,meningitis, peritonitis,mastitis, septicemia and Gram-negative pneumonia.

What is Escherichia coli O157:H7?

E. coli O157:H7 is one of hundreds of strains of the bacterium Escherichia coli. Although most strains are harmless, this strain produces a powerful toxin that can cause severe illness. E. coli O157:H7 has been found in the intestines of healthy cattle, deer, goats, and sheep.
Infection with E. coli often leads to bloody diarrhea, and occasionally to kidney failure. People can become infected with E.coli O157:H7 in a variety of ways. Though most illness has been associated with eating undercooked, contaminated ground beef, people have also become ill from eating contaminated bean sprouts or fresh leafy vegetables such as lettuce and spinach. Person-to-person contact in families and child care centers is also a known mode of transmission. In addition, infection can occur after drinking raw milk and after swimming in or drinking sewage-contaminated water.
Consumers can prevent E. coli O157:H7 infection by thoroughly cooking ground beef, avoiding unpasteurized milk, and by washing hands carefully before preparing or eating food. Fruits and vegetables should be washed well, but washing may not remove all contamination. Public service announcements on television, radio, or in the newspapers will advise you which foods to avoid in the event of an outbreak.
Because the organism lives in the intestines of healthy cattle, preventive measures on cattle farms, during meat processing, and during the growth, harvest and processing of produce are being investigated.

How is E. coli O157:H7 infection diagnosed?

Infection with E. coli O157:H7 is diagnosed by detecting the bacterium in the stool.
When a person is contaminated with the bacteria, they do not immediately show symptoms of the illness. This is because there is an incubation period from anywhere between 3 and 9 days, during which is it possible to spread the bacteria When a person is infected, the bacterium travels through their stomach and into their small intestines. Afterwards, it travels to the large intestine and attaches itself to the inside surface of the large intestine. Here, the toxins that are released by the bacteria cause the walls of the large intestine to become irritated and inflamed. Once the bacterium manifests itself within large intestines of a person, they then begin to experience the illness. The first of many symptom people usually experience is hemorrhagic colitis, which is sudden arrival of abdominal pain and cramping. These cramps are quite often very painful and abrupt. This primary symptom is then followed by diarrhea, usually within 24 hours of the onset of the abdominal pain. As time goes on, the diarrhea will become watery and bloody. Also, vomiting is another possible symptom, but there is rarely a fever associated with this illness. Unfortunately for the affected person, these symptoms will continue for the duration of the sickness, which is about a week, and there are no medicines or antibiotics that are available for their symptoms.

Bacterial meningitis

Bacterial meningitis is a condition in which the dural layers lining the brain (the meninges) have become inflamed.
The classic symptoms of bacterial meningitis are similar to those of other forms of meningitis, including fever, headache, light sensitivity (photophobia), and confusion.


is the inflammation of the protective membranes covering the central nervous system, known collectively as the meninges. Meningitis may develop in response to a number of causes, including infectious agents, physical injury, cancer, or certain drugs. While some forms of meningitis are mild and resolve on their own, meningitis is a potentially serious condition owing to the proximity of the inflammation to the brain and spinal cord. The potential for serious neurological damage or even death necessitates prompt medical attention and evaluation. Infectious meningitis, the most common form, is typically treated with antibiotics and requires close observation.

Sources: CDC, Sciencie Dayli

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