E. COLI & E. COLI 0157 H7

Description

E. coli is the abbreviated name of the bacterium in the Family Enterobacteriaceae named Escherichia (esh-er-eek'-ee-a) (Genus) coli (Species). E.coli is a Gram negative bacillus. The Family to which E. coli belongs, (Enterobacteriaceae), is so named because of the Greek word enterikos - which pertains to the intestine. The name Escherichia comes from the name of the person Escherich, who first isolated and characterized this bacterium in 1885.

Approximately 0.1% of the total bacteria within an adult's intestines (on a Western diet) is represented by E. coli. Although in a newborn infant's intestines E. coli, along with lactobacilli and enterococci, represent the most abundant bacterial flora. In fact, it is for this reason that the organisms which inhabit the intestinal tract as normal flora are named enteric bacteria.

E Coli: good guys

For the most part the presence of E. coli and other kinds of bacteria within our intestines are necessary for us to develop and function properly, and for us to remain healthy. E.coli, along with other species of bacteria, provides us with many necessary vitamins for example. The bacteria make the vitamins, and our bodies absorb and benefit from them. We pretty much depend upon E. coli in our intestines for our source of Vitamin K and B-complex vitamins.

The fetus of any animal is completely sterile. Immediately after birth however, the newborn acquires all kinds of different bacteria which live symbiotically (we help them to live, and they help us to live) with the newborn and throughout the individual's life. From the day we are born, we are never without bacteria. However, the helpful bacteria like these are located only in regions of our body directly exposed to the environment, such as intestines, upper and lower respiratory tract, and never within our bloodstream or the tissues inside our body. Indeed, animals that are born and raised ""germ free"" are really wimpy; they have thin intestinal walls, puny heart output, and require lots of vitamin supplements just to stay alive.

E Coli: bad guys

Bacteria are somewhat like humans in that certain individual humans are not very nice, and we know that some individual humans can be downright dangerous. So, as there exists individual humans, so too can different individuals exist among E. coli bacteria. We call such individuals a different ""strain"" of bacteria within a given species. There are literally hundreds of strains of the bacterium Escherichia coli.

Escherichia coli O157:H7 is an emerging cause of foodborne illness. This rare strain is getting a lot of press lately because it is indeed a bad bug. E.coli O157:H7 is a member of the enterohemorrhagic E. coli group (EHEC). (Enterohemorrhagic means an intestinally-related organism which causes hemorrhaging.)

In the case of E.coli O157:H7, a long-ago "Good Guy" cell appears to have been infected with a bacterial virus. This particular virus had the ability to insert its own DNA into the bacteria's chromosome without harming the organism. This virus's genetic information contained information for the production of a toxin, called Shiga-like toxin (SLT), sometimes called Vero toxin. The toxin is a protein which causes severe damage to intestinal epithelial cells (the cells that line the wall of the intestine). The damage is so severe that if we acquire this bacterial strain, not only do we lose water and salts, but blood vessels are damaged, and bleeding occurs. This condition is particularly dangerous to small children, and may be lethal as they are too small to tolerate much blood and fluid loss.

"This strain was first recognized in 1982 when an outbreak of hemorrhagic colitis occurred in the USA. The diarrhea that this strain produces ranges from mild and non-bloody, to stools that are virtually all blood. In some persons, particularly children under 5 years of age and the elderly, the infection can also cause a complication called hemolytic uremic syndrome, (HUS), in which the red blood cells 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 are caused by E. coli O157:H7. An estimated 73,000 cases of infection and 61 deaths occur in the United States each year.

Where are they found?

The organism (E.coli O157:H7) can be found on a small number of cattle farms and 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 the organism can cause infection. Contaminated meat looks and smells normal. Although the number of organisms required causing disease is not known, it is suspected to be very small.

Incubation period

Symptoms usually appear within 2 to 4 days, but can take up to 8 days.

Treatment

Most persons recover without antibiotics or other specific treatment in 5 to 10 days. There is no evidence that antibiotics improve the course of the disease, and it is thought that treatment with some antibiotics may precipitate kidney complications. Antidiarrheal agents, such as loperamide (Imodium), should also be avoided. Persons who only have diarrhea usually recover completely. About one third of persons with hemolitic uremic syndrome have abnormal kidney function many years later with some requiring long-term dialysis. Another 8% with HUS can experience life long complications.

Prevention

1. Always clean and disinfect any surface that has come in contact with raw meat, before any other item is placed on that surface.
2. Always thoroughly wash your hands after handling raw meat, and before you handle any other utensils or other food items.
3. Never use the same plate, tray or utensils for the cooked meat that you use for the raw meat - unless you thoroughly wash the plate, tray or utensils in-between.
4. Always cook meat, especially ground meat, until the juices run absolutely clear - pink is not good enough. In fact, it is necessary for the internal temperature of a hamburger patty to reach 160 degrees F to kill all of any contaminating E. coli.
5. In homecare settings, day-care centers, schools, etc., any small children with diarrhea should be handled carefully, and kept separate from all well children. All diapers, and any soiled clothing should be kept separate from all well children. The day-care worker, teacher, and health-care personnel should practice strict hygiene at all times, regardless of the health of children.
6. Drink only pasteurized milk, juice, or cider. Commercial juice with an extended shelf-life that is sold at room temperature (e.g. juice in cardboard boxes, vacuum sealed juice in glass containers) has been pasteurized, although this is generally not indicated on the label. Juice concentrates are also heated sufficiently to kill pathogens.
7. Wash fruits and vegetables thoroughly, especially those that will not be cooked. Children under 5 years of age, immunocompromised persons, and the elderly should avoid eating alfalfa sprouts until their safety can be assured. Methods to decontaminate alfalfa seeds and sprouts are being investigated.
8. Drink municipal water that has been treated with chlorine or other effective disinfectants.
9. Avoid swallowing lake or pool water while swimming.