Escherichia coli (E. coli)

Pathogens 101 | Escherichia coli (E. coli)

E. coli bacteria

What is E. coli?
Escherichia coli (abbreviated as E. coli) are a large and diverse group of Gram-negative, bacilli bacteria that normally live in the intestines of people and animals. Most E. coli are harmless and actually are an important part of a healthy human intestinal tract. However, some E. coli are pathogenic, meaning they can cause illness, either diarrhea or illness outside of the intestinal tract. Pathogenic E. coli strains are categorized into pathotypes. Six pathotypes are associated with diarrhea and collectively are referred to as diarrheagenic E. coli. The types of E. coli that can cause diarrhea can be transmitted through contaminated water or food, or through contact with animals or persons.

How is E. coli O157:H7 spread?
The organism can live in the intestines of healthy cattle. Meat can become contaminated during slaughter, and organisms can be thoroughly mixed into beef when it is ground. Bacteria present on the cow’s udders or on equipment may get into raw milk. Eating meat, especially ground beef that has not been cooked sufficiently to kill E. coli O157:H7 can cause infection. Contaminated meat looks and smells normal. Although the number of organisms required to cause disease is not known, it is suspected to be very small. Among other known sources of infection is consumption of sprouts, lettuce, salami, unpasteurized milk and juice, and swimming in or drinking sewage-contaminated water. Bacteria in diarrheal stools of infected persons can be passed from one person to another if hygiene or handwashing habits are inadequate. This is particularly likely among toddlers who are not toilet trained. Family members and playmates of these children are at high risk of becoming infected.

Complications of E. coli O157:H7
Some victims, particularly the very young, can develop a very serious complication, Hemolytic Uremic Syndrome (HUS) which can lead to kidney failure and death. HUS, if it occurs, develops an average seven days after the first symptoms when the diarrhea is improving. HUS can lead to life-long complications. In an older population, Thrombotic Thrombocytopenic Purpura (TTP) may be seen. Neurologic symptoms may also be experienced, as well as pancreatitis, diabetes, and high blood pressure.

Treatment of E. coli O157:H7
Treatment often just consists of supportive care, with close monitoring of kidney (renal) functioning, hemoglobin, and platelet counts. Antibiotics may be contraindicated since studies have shown they may promote the development of HUS. Anti-diarrheal agents may also increase the risk of HUS.

Is E. coli O157:H7 killed by freezing?
Freezing does not destroy these bacteria. E. coli O157:H7 survive refrigerator and freezer temperatures.

Nationally Notifiable
E. coli O157:H7 is nationally notifiable. Physicians and labs should report cases to their state health department and the Centers for Disease Control and Prevention (CDC).

E.coli O157:H7 is a potentially deadly bacterium that can cause bloody diarrhea, dehydration, and in the most severe cases, kidney failure. The very young, seniors and persons with weak immune systems are the most susceptible to foodborne illness.

Food contaminated with E. coli O157:H7 may not look or smell spoiled. Consumption of food contaminated with these bacteria my cause serious and potentially life-threatening illnesses. E. Coli O157:H7 is a potentially deadly bacterium that can cause dehydration, bloody diarrhea and abdominal cramps 2-8 days (3-4 days, on average) after exposure to the organism.

While most people recover within a week, some develop a type of kidney failure called Hemolytic Uremic Syndrome (HUS). This condition can occur among persons of any age but is most common in children under 5-years old and older adults. Symptoms of HUS may include fever, abdominal pain, pale skin tone, fatigue and irritability, small, unexplained bruises or bleeding from the nose and mouth, decreased urination, and swelling.

Persons who experience these symptoms should seek emergency medical care immediately.

Many clinical laboratories do not test for non-O157 Shiga toxin-producing E. coli (STEC), such as STEC O26, O103, O45, O111, O121 or O145 because it is harder to identify.

 

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