E. coli 0157:H7 was first isolated in 1982 when forty seven people in Michigan and Oregon became violently ill.
The bacterium contained a few strands of genetic material that cause it to produce a Shigella type toxin.
Scientists believe the toxin first destroys blood vessels in the intestine, causing bloody diarrhea. Bloody diarrhea is the most telling symptom of this type of E. coli infection.
Most people experience bloody diarrhea and abdominal pain and recover but about 2 to 7 percent develop hemolytic uremic syndrome (HUS).
Although rare up until the 1980s, HUS is a disease of the blood and kidneys that is now the leading cause of kidney failure in US and Canadian children.
Hemolytic Uremic syndrome (HUS) develops when the toxin penetrates the intestine wall and passes into bloodstream.
Once in the blood stream. The toxin damages vessels throughout the body.
When the E. coli toxins enter the blood stream, they shred cells. The debris clogs the kidneys. After the kidneys fail other organs are affected including the heart, lungs and central nervous system.
There is no cure. In fact, treatment with antibiotics is thought to exacerbate the condition because the antibiotic kill beneficial bacteria, ,leaving more resources for the E. coli 0157:H7.
Antibiotics can also weaken the toxin E. coli bacteria causing it to release more toxins.
E. coli 0157:H7 is most commonly associated with cattle. it does not harm the 1 to 2 percent of cattle that carry the bacteria in their intestines.
Transmission of the bacteria can occur during the slaughter process.
Sometimes fecal matter from the intestines contaminates the meat. If the meat is ground to make hamburger the bacteria is spread throughout the meat.
Since most meat made into hamburger is pooled from many animals, contamination from one carcass can infect large batches of meat.
Since contamination can occur throughout the entire hamburger patty, a burger must be thoroughly cooked and reach an internal temperature of 160 degrees Fahrenheit to be safe.
Escherichia coli 0157:H7
