E. coli O157 and other Shiga toxin-producing E. coli (STEC)
What is E. coli?
There are many types of Escherichia coli (E. coli) bacteria that live in the intestinal tract and many do not cause human illness. Shiga toxin-producing E. coli (STEC), including E. coli serotype O157, is a specific type of E. coli that can cause illness ranging from mild intestinal symptoms to severe kidney complications. E. coli O157 infection in young children may lead to potentially life-threatening complications such as hemolytic uremic syndrome. STEC infections occur throughout the year with a peak during the summer months. Cattle are the most common source of STEC though other animals such as deer, elk, goats, and sheep can also carry STEC. In addition, humans also transmit STEC.
Signs and symptoms
- Diarrhea, which can be bloody
- Abdominal cramps
- Sometimes nausea
- Low-grade or no fever
- Vomiting
- Hemolytic uremic syndrome
Incubation Period
Ranges from one to 10 days (usually three to four days)
Contagious period and spread
- STEC infection is spread through the fecal→oral route. People can become ill with STEC by eating contaminated food (especially undercooked meats and leafy greens); drinking or swimming in contaminated water; or having contact with animals or their feces, such as at a petting zoo or farm.
- STEC is highly contagious and can spread person-to-person, especially in child care and preschool facilities.
- STEC can be spread as long as the bacteria is in the stool, typically one to four weeks, even after symptoms have resolved.
Public health reporting requirements
- Staff who become aware of the illness should report the infection to the facility director, school nurse, or child care health consultant.
- The facility should report individual cases to the local or state health department within four days of diagnosis.
- If other children or staff are ill with diarrhea, refer them to their health care providers and contact public health as soon as possible as this could be an outbreak. Generally speaking, it is considered an outbreak if there is an increase in the number of ill children and/or staff members at the school or child care facility, or two or more cases of STEC from different households.
- Suspected outbreaks should be reported to CDPHE or local health departments within four hours, even if the causative agent is not yet known.
Control of spread
- STEC can spread quickly through child care centers, but can be controlled if appropriate action is taken.
- Consult with local or state public health on implementation of control measures.
- Encourage and teach the importance of frequent handwashing, especially after animal contact, after using the toilet, changing diapers, and before eating. Directly supervise handwashing of children aged 5 years or younger. Sample signs showing when and how to wash hands are included in the department’s child care health regulations webpage under “Preventing illness” and in the hand hygiene section of this site. Post them or similar signs throughout the child care center or school to remind people to wash their hands.
- Promptly sanitize contaminated surfaces (like diaper-changing areas) and other commonly touched surfaces (like toys) and discard food or water if it is thought to be contaminated. See Disease Prevention: The Facility Environment.
- Refer to Disease Prevention: Food Safety for information on food safety.
- Alert possibly exposed family and staff members to watch for symptoms, and provide them with prevention tips. See recommendations for caregivers and the family section below.
Treatment
Most people with healthy immune systems will recover without treatment within five to seven days. Antibiotics are generally not indicated for treatment of STEC because they may increase the risk of developing hemolytic uremic syndrome (HUS). People with STEC infection should be given plenty of fluids to prevent dehydration.
Anti-diarrheal drugs may also increase the risk of HUS and should not be given to children with inflammatory or bloody diarrhea. Careful follow-up of patients with hemorrhagic colitis is recommended to detect changes suggestive of HUS.
Exclusion
- Child care and preschool
- EXCLUDE all children, staff, and caregivers infected with STEC until cleared by public health. Clearance by public health may require two consecutive negative stools collected 24 hours apart.
- Ill children should not go to another facility during the period of exclusion.
- When a case of STEC is identified in a child attending child care, determine whether additional children have or have recently had diarrhea. Other children with diarrhea should be excluded, seen by their physician, and submit stool for STEC testing. If other cases in the center are identified, work with public health to consider sending a letter home to parents/guardians/caregivers.
- If the case is the only child in the classroom or center who has been ill, no further action is indicated for other children in that classroom or center.
- Consult with public health to determine if staff with no role in food preparation or feeding (e.g. office staff) may return to work after diarrhea has been resolved for at least 24 hours or if they will need follow-up stool testing.
- Primary and secondary school
- Students or staff with STEC infection should be excluded until at least 24 hours after their diarrhea has resolved, without the use of anti-diarrheal medications.
- Children who wear diapers or have developmental delays resulting in fecal incontinence or hygiene concerns should be excluded until cleared by public health which may require negative testing.
- Students or staff who handle food and have an STEC infection must not prepare food until at least 24 hours after their diarrhea has resolved, and they have two consecutive negative stool tests taken at least 24 hours apart.
Role of teachers, caregivers, and family
- If your child or a child you care for is infected with STEC, follow the advice of the child’s health care provider.
- It is important to practice good handwashing, especially after changing diapers, going to the bathroom or helping a child go to the bathroom, or handling food.
- Diapering, bathroom, and food preparation areas should be cleaned and disinfected frequently.
- Wash hands after touching pets or other animals as they can carry STEC.
- Keep food that will be eaten raw, such as vegetables, from becoming contaminated by animal-derived food products, and thoroughly cook all ground beef, hamburger, and needle-tenderized beef products to an internal temperature of at least 160°F.
- Avoid consuming or serving unpasteurized milk, unpasteurized dairy products, or unpasteurized juices, like fresh apple cider.
- Infected individuals should not swim or wade in pools or other recreational water while experiencing diarrhea.