Escherichia Coli O157: H7 Foodborne Disease

Clinical Features

• Acute bloody diarrhea and abdominal cramps with little or no fever.
• Lasts 5-10 days.

Etiologic Agent

• Escherichia coli serotype O157:H7.
• A gram negative rod-shaped bacterium producing Shiga-like toxin(s).

Incidence

• Reported rates in developed countries are 5-8 cases/100,000 population per year, with regional variations.
• Rarely reported in patients in less developed countries.

Sequelae

• Hemolytic uremic syndrome (HUS); persons with this illness have kidney failure and usually require dialysis.
• Some have neurologic impairment, such as seizures or blindness.
• Most survive but some have residual high blood pressure and kidney impairment.
• Surgery to remove part of the bowel (usually because of misdiagnosis).
• Death (1-2% of E. coli O157:H7 cases; 3-5% of HUS cases).

Costs

• Patients are often hospitalized.
• The illness is often misdiagnosed, so expensive diagnostic procedures may be performed.
• Patients who develop hemolytic uremic syndrome often require prolonged hospitalization, dialysis, and long term follow-up.

Transmission

• Major sources are ground beef and raw milk.
• Waterborne transmission has occurred.
• Organism is easily transmitted from person to person, and has been difficult to control in child day care centers.

Risk Groups

Persons at extremes of age (children under 5 years and elderly)

Surveillance

E. coli O157:H7 infection is nationally reportable; it is reportable in more than half the U.S. states.

Trends

Reported infections in developed countries have increased markedly since this illness was first described in 1982

Challenges

• Educate the American public to cook ground beef well and to eat it only if cooked "well done".
• Educate physicians regarding manifestations of disease and differential diagnosis.
• Institute national surveillance for HUS.
• Identify other vehicles of transmission.
• Teach clinical laboratories the benefits of screening stools for this pathogen.
• Develop methods to decrease contamination of ground beef.
• Define ecology of the organism in animal reservoirs.

Opportunities

• Transmission of this serious illness in day care centers highlights the need for better infection control practices.
• Learning more about the ecology of this organism in cattle may help in devising methods to decrease prevalence of this and other human pathogens in food animals.
• Decreasing the incidence of these infections would decrease the incidence of HUS, which is the major cause of acute kidney failure in children in the U.S..

Research Priorities

• Conduct trials of agents that may decrease severity of illness and risk of complications.
• Determine risk factors for complications.
• Determine the magnitude of the animal reservoir.
• Determine mechanisms to prevent contamination of meat during slaughter and processing.

March 1996
Courtesy of the Centers for Disease Control and Prevention