E. coli O157:H7 is a common cause of foodborne outbreaks. It has been associated with hamburger, apple juice, and unpasteurized dairy products. Although most infections are not serious and resolve on their own, potentially deadly complications can occur following infections by E. coli O157:H7.
Species Name: Enterohemorrhagic Escherichia coli, or “EHEC”
Type of Microbe: Gram-negative bacteria
How it spreads: Usually foodborne. Foods associated with E. coli have included raw or undercooked meats (e.g., ground beef), deli meats, unpasteurized fruit juices and dairy products, and produce. Other sources of infection have included petting zoos, lake water, and contaminated hands.
Who’s at risk? All people are susceptible to the disease, but the very young and very old are at greater risk for more serious disease.
Symptoms: Symptoms may vary, but usually include diarrhea (usually bloody), vomiting, and severe stomach cramps. Typically, fever is absent or very mild. For most people, the infection resolves by around 8 days.
Diagnosis: Lab testing of stool samples is performed with bacterial cultures.
Prognosis: Most infections resolve on their own within 5 to 7 days without treatment, but some infections can be severe or life-threatening (see complications below).
Treatment: There are no drugs recommended for treating E. coli O157:H7 infections. Use of antibiotics and/or anti-diarrheal medications, such as Immodium, has been associated with an increased risk for a potentially life-threatening condition known as hemolytic-uremic syndrome (see Complications below).
Prevention:Use good hygiene, frequent hand washing, and kitchen safety practices.
How it causes disease: E. coli attaches to intestinal cells and produces a toxin that causes inflammation and secretion of intestinal fluids. The toxin also damages the tissue lining of the large intestine and kidneys.
Complications: About 5-10% of individuals with E. coli O157:H7 infections develop a potentially fatal complication called hemolytic-uremic syndrome, or HUS, which is characterized by kidney or renal failure and hemolytic anemia (loss of red blood cells). This condition usually occurs in children and can be quite serious, leading to permanent kidney damage or death.
Sources: Escherichia coli. CDC Division of Foodborne, Bacterial and Mycotic Diseases.
Escherichia coli O157:H7. US FDA Bad Bug Book. Foodborne Pathogenic Microorganisms and Natural Toxins Handbook.
