E.coli O157:H7

Gram-negative rod that is motile, aerobic and produces 2 types of Vero / Shiga toxins, and fairly resistant to moderate acidity.

Incubation period

Usually 3-4 days, may be as short as 1 day or as long as 10 days.

Symptoms

Diarrhea that is severe and often escalates to very bloody, known as hemorrhagic colitis. Abdominal pain, and vomiting may also be present. Fevers will be low grade or absent and are more common in children under 4 years of age.

Illness duration

Self-limiting illnesses will last on average from 5-10 days.

Complications

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 7 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.

Infective dose

Not fully understood, thought to be as few as 10 organisms

Treatments

Often just 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, antidiarrheal agents may also increase the risk of HUS.

Testing

Stool cultures can be used to test for the bacteria, serum cultures can detect the presence of the Shigatoxin.

Communicability

Communicable for duration of fecal excretion (average is 7-9 days); as long as 3 weeks in some children

Nationally Notifiable

This disease is nationally notifiable, physicians and labs should report cases to their state health department and the Center's for Disease Control (CDC).