DISEASE

E Coli Infection

OVERVIEW | CAUSES | RISK FACTORS | SYMPTOMS | COMPLICATION | DIAGNOSIS | TREATMENT | PREVENTION | REFERENCES

E Coli Infection

OVERVIEW

Escherichia coli (E. coli) bacteria normally live in the intestines of healthy people and animals. Most types of E. coli are harmless or cause relatively brief diarrhea. But a few strains, such as E. coli O157:H7, can cause severe stomach cramps, bloody diarrhea and vomiting.

You may be exposed to E. coli from contaminated water or food — especially raw vegetables and undercooked ground beef. Healthy adults usually recover from infection with E. coli O157:H7 within a week. Young children and older adults have a greater risk of developing a life-threatening form of kidney failure.

CAUSES

Only a few strains of E. coli trigger diarrhea. The E. coli O157:H7 strain belongs to a group of E. coli that produces a powerful toxin that damages the lining of the small intestine. This can cause bloody diarrhea. You develop an E. coli infection when you ingest this strain of bacteria.

Unlike many other disease-causing bacteria, E. coli can cause an infection even if you ingest only small amounts. Because of this, you can be sickened by E. coli from eating a slightly undercooked hamburger or from swallowing a mouthful of contaminated pool water.

Potential sources of exposure include contaminated food or water and person-to-person contact.

Contaminated food

The most common way to get an E. coli infection is by eating contaminated food, such as:

Ground beef. When cattle are slaughtered and processed, E. coli bacteria in their intestines can get on the meat. Ground beef combines meat from many different animals, increasing the risk of contamination.
Unpasteurized milk. E. coli bacteria on a cow's udder or on milking equipment can get into raw milk.
Fresh produce. Runoff from cattle farms can contaminate fields where fresh produce is grown. Certain vegetables, such as spinach and lettuce, are particularly vulnerable to this type of contamination.

Contaminated water

Human and animal stool may pollute ground and surface water, including streams, rivers, lakes and water used to irrigate crops. Although public water systems use chlorine, ultraviolet light or ozone to kill E. coli, some E. coli outbreaks have been linked to contaminated municipal water supplies.

Private water wells are a greater cause for concern because many don't have a way to disinfect water. Rural water supplies are the most likely to be contaminated. Some people also have been infected with E. coli after swimming in pools or lakes contaminated with stool.

Personal contact

E. coli bacteria can easily travel from person to person, especially when infected adults and children don't wash their hands properly. Family members of young children with E. coli infection are especially likely to get it themselves. Outbreaks have also occurred among children visiting petting zoos and in animal barns at county fairs.

RISK FACTORS

E. coli can affect anyone who is exposed to the bacteria. But some people are more likely to develop problems than are others. Risk factors include:

Age. Young children and older adults are at higher risk of experiencing illness caused by E. coli and more-serious complications from the infection.
Weakened immune systems. People who have weakened immune systems — from AIDS or from drugs to treat cancer or prevent the rejection of organ transplants — are more likely to become ill from ingesting E. coli.
Eating certain types of food. Riskier foods include undercooked hamburger; unpasteurized milk, apple juice or cider; and soft cheeses made from raw milk.
Time of year. Though it's not clear why, the majority of E. coli infections occur from June through September.
Decreased stomach acid levels. Stomach acid offers some protection against E. coli. If you take medications to reduce stomach acid, such as esomeprazole (Nexium), pantoprazole (Protonix), lansoprazole (Prevacid) and omeprazole (Prilosec), you may increase your risk of an E. coli infection.

SYMPTOMS

Signs and symptoms of E. coli O157:H7 infection usually begin three or four days after exposure to the bacteria. But you may become ill as soon as one day after exposure to more than a week later. Signs and symptoms include:

Diarrhea, which may range from mild and watery to severe and bloody
Stomach cramping, pain or tenderness
Nausea and vomiting, in some people

COMPLICATIONS

Most healthy adults recover from E. coli illness within a week. Some people — particularly young children and older adults — may develop a life-threatening form of kidney failure called hemolytic uremic syndrome.

DIAGNOSIS

To diagnose illness caused by E. coli infection, your doctor sends a sample of your stool to a laboratory to test for the presence of E. coli bacteria. The bacteria may be cultured to confirm the diagnosis and identify specific toxins, such as those produced by E. coli O157:H7.

TREATMENT

For illness caused by E. coli, no current treatments can cure the infection, relieve symptoms or prevent complications. For most people, treatment includes:

Rest
Fluids to help prevent dehydration and fatigue

Avoid taking an anti-diarrheal medication — this slows your digestive system down, preventing your body from getting rid of the toxins. Antibiotics generally aren't recommended because they can increase the risk of serious complications and they don't appear to help treat the infection.

If you have a serious E. coli infection that has caused a life-threatening form of kidney failure (hemolytic uremic syndrome), you'll be hospitalized. Treatment includes IV fluids, blood transfusions and kidney dialysis.

PREVENTION

The most important thing you can do to protect against E. coli infection is to wash your hands – frequently. Always wash your hands thoroughly before and after cooking and after handling raw meat or poultry.

Wash your hands after using the restroom, changing diapers or after contact with animals.

If you’ve been infected with E. coli, scrub your hands vigorously with soap and clean under your fingernails where bacteria can get caught. Dry your hands with paper towels instead of cloth towels to avoid transferring bacteria.

You can also reduce your risk of an E. coli infection by following these food preparation and cooking tips.

When thawing meats

Don’t defrost frozen meat unwrapped on the counter.
Keep frozen meat in a separate plastic bag (for example, a plastic grocery bag) when thawing.

When prepping foods

Don’t rinse meat before cooking. It’s not necessary. Washing the meat could spread bacteria to nearby surfaces, utensils and other food.
Use a plastic or ceramic cutting board to cut raw meat. These materials can be cleaned more easily and thoroughly than wooden cutting boards.
Don’t “cross-contaminate” a prepping surface. If you have raw meat or chicken on a prepping surface, such as a cutting board, wash it thoroughly with soap and hot water before putting another type of food (such as a raw vegetable) on it. Better yet, use different cutting boards for the foods you are preparing.
Rinse all raw fruits and vegetables under cold running water before eating them. It’s ok to scrub firm produce but don’t use detergent or soap.

When cooking and serving meats:

Cook all meat well (undercooked meat is another source of E. coli contamination). Cooking foods well kills bacteria.
Don’t put a cooked hamburger on a plate that had raw meat on it.
Refrigerate leftovers right away.