Controlling Spread of E. Coli

A. Isolation and Quarantine Requirements

In the healthcare setting patients should be placed in contact isolation for the duration of the diarrhea.

In homes, persons with diarrhea should not cook food for others and must use good handwashing technique after using the toilet.

Cases must be instructed on proper handwashing, especially after-toilet use.

B. Managing Special Situations

Foodhandlers

Contacts with diarrhea who are food handlers shall be considered a case and handled in the same fashion.

 Food handlers with pathogenic E. coli must be excluded from work. A food handler is any person directly preparing or handling food. This can include a patient-care or child-care provider.

No foodservice worker, healthcare or child care provider should be at work while experiencing active diarrhea.

After diarrhea has resolved, food-handling employees may only return to food handling after producing two negative stool tests taken at least 24 hours apart. If a case has been treated with an antimicrobial, the stool specimens shall not be submitted until at least 48 hours after cessation of therapy. Food handling employees may be reassigned to tasks where they do not handle food once they have had no diarrhea for 24 hours while awaiting the two negative stool tests. 

Households

Enteric diseases spread easily through households because both close, personal contact and foodborne modes of transmission can be involved. The case interview should provide valuable information about the household that can give clues to the most likely source of the illness. This will also help identify possible vehicles for transmission to other family/household members.

Person-to-person transmission of enteric disease among household members (or household-like contacts) occurs very readily. The potential for transmission is greater if any of the following risk factors are present in the household:

•       Diapered children, especially toddlers.
•       Crowded, unsanitary conditions.
•       Lack of adequate handwashing facilities
•       A fecally incontinent adult who is cared for by other household members.
•       Any activity in which contact with feces is likely.
•       Situations where enteric diseases can be sexually transmitted (e.g. homosexual males)

The steps in assessment of the household are:

1. Try to determine whether the source of the illness was in the household (either via person-to-person transmission or a common source, such as food).
2. Teach about foodborne and person-to-person transmission patterns, which can occur within the household.  Provide fact sheets.
3. If other household members are ill, determine if they are at high risk for transmission outside the household (child care, food establishment, patient care). (See guidelines for specific high-risk setting.)
4. Make recommendations for exclusion from work and/or cohorting/exclusion from child care if indicated. (See guidelines for specific high-risk setting
5. Report case(s) to CADE; IDSS is the preferred method 
6. If household contacts are in high-risk settings, and are having symptoms, they should be excluded from the high-risk situation and a stool test done. If the household contacts are in high risk settings, but have no symptoms, instruct them on good hygiene, and warn if symptoms develop they should exclude themselves immediately from the high risk situation and have a stool test done.

Child Care

The role that child care centers play in the transmission of enteric diseases has been well documented. Because young children lack hygiene skills, are not always fecally continent (in diapers), and are highly mobile, they serve as very efficient "spreaders" of enteric organisms. Child care employees may also contribute to the spread of enteric diseases if they care for other children or prepare food without properly washing their hands after changing diapers. However, food and water are rarely vehicles for transmission in child care centers. Enteric diseases are commonly spread from person to person as a result of the combination of poor hygiene and highly infectious enteric pathogens. Since E. coli may be transmitted person-to-person through fecal-oral transmission, it is important to follow up on cases of pathogenic E. coli in a child care setting carefully. General recommendations include:

• Children with pathogenic E. coli should be excluded until two negative stool cultures taken more than 24 hours apart are obtained. If a case has been treated with an antimicrobial, the stool specimens shall not be submitted until at least 48 hours after cessation of therapy.
• Staff with diarrhea due to pathogenic E.coli should not return to food handling work or direct child care until they have had 2 negative stool cultures taken at least 24 hours or apart and not sooner than 48 hours following the discontinuation of antibiotics. 

• Staff of child care programs are considered food handlers. No one should be at work with active diarrhea.

School

Since E. coli may be transmitted person-to-person through fecal-oral transmission, it is important to follow up on cases of pathogenic E. coli in a school setting carefully. General recommendations include:

• Students or staff with E. coli infection who have diarrhea should be excluded until their diarrhea is gone.
• Students or staff with E. coli who do not have diarrhea or vomiting and do not handle food may remain in school if proper hygienic practices are maintained.
• Students or staff who handle food and have E. coli infection (symptomatic or not) should not prepare food until their diarrhea is gone and they have had two negative stool tests (submitted at least 48 hours after completion of antibiotic therapy, and at least 24 hours apart, if antibiotics are given).

Patient Care Settings

Reports of enteric disease in patient-care settings should be followed up as soon as possible, since outbreaks among the ill and elderly may cause significant morbidity and mortality. When a case of shiga-toxin producing E. coli occurs in a patient-care setting, the local public health agency (LPHA) may be called upon to assess the potential for transmission and to recommend interventions to prevent further transmission to patients/residents or other staff members.

 A.  Assessment of Potential for Transmission by a Health-care Worker (HCW)                      

1. Obtain and review a description of the HCW duties.

2. Determine the presence of acute diarrhea.

B. Prevention of Transmission                       

1. If the HCW does have contact with the patient, the patient’s environment or food and has diarrhea, exclude from work until diarrhea is resolved and two  stool cultures collected at least 24 hours apart and at least 48 hours after discontinuation of antibiotics are negative. Once they have had no diarrhea for 24 hours they can be assigned to duties not involving contact with patient, patient environment or food while awaiting negative stool testing.
2. If the person with a shiga-toxin producing E. coli disease is a patient or resident in a hospital, nursing home or other residential care facility, Contact Precautions should be followed until the patient is free of diarrhea. Standard Precautions should be used at all times.

 Contact Precautions                     

1. Gowns and gloves should be worn when handling the patient's feces or fecally soiled items such as the patient's bed linens, towels, washcloths and clothing. In addition, wear gowns when entering the room if it is anticipated that clothing will have substantial contact with environmental surfaces, items in the environment, or if the patient is incontinent.
2. If rinsing is necessary, fecally soiled clothing and linens should be rinsed only in a commode or hopper sink designed for this purpose. Never rinse in a handwashing sink!
3. The patient's soiled clothing and linens should be bagged in bags that do not leak through for transport to the laundry.
4. If at all possible, use disposable diapers for incontinent patients.
5. Articles used to care for the patient should be used only for that patient until diarrhea is resolved.  This would include blood pressure cuff, stethoscope, thermometer, etc.
6. As always, hands should be washed thoroughly after caring for each patient. Patient’s hands should also be washed.

Community Residential Programs

Actions taken in response to a case of pathogenic E. coli in a community residential program will depend on the type of program and the level of functioning of the residents.

In long-term care facilities, residents with pathogenic E. coli should be placed on Contact Precautions until their symptoms subside.

Staff members who give direct patient care that includes oral contact (e.g., feed patients, give mouth or denture care, or give medications) are considered food handlers and are subject to food handler restrictions, meaning they should not return to those duties until they have 2 negative stool cultures taken at least 24 hours apart and not sooner than 48 hours following the discontinuation of antibiotics. Once they have had no diarrhea for 24 hours they can be assigned to duties other than patient care or food handling. In addition, staff members with E. coli infection who are not food handlers should not work until their diarrhea is gone. 

In residential facilities for the developmentally disabled, staff and clients with E. coli should refrain from handling or preparing food for other residents until their diarrhea has subsided and they have had 2  negative stool cultures taken at least 24 hours  apart and not sooner than 48 hours following the discontinuation of antibiotics. In addition, staff members with E. coli infection who are not food handlers should not work until their diarrhea is gone.

Household Contacts Employed In High Risk Occupations

Household contacts should be questioned about their employment in high-risk occupations such as food handling, direct patient care, or child care establishments. All household contacts should be educated about the symptoms of the disease and about hygienic methods to avoid further transmission. Proper hand hygiene should be stressed. If they have symptoms, a stool test should be done.

Household contacts that are symptomatic and employed as food handlers, child care workers, or persons responsible for direct patient care should be excluded from their duties until their diarrhea ceases. Household contacts with pathogenic E. coli should not return to food handling or direct child or patient care until they have had 2 negative stool cultures taken at least 24 hours apart and not sooner than 48 hours following the discontinuation of antibiotics. Once they have had no diarrhea for 24 hours they can be assigned to duties other than patient care or food handling. They should all be educated on good hygiene, not to work if they become ill, and if diarrhea develops they should be tested and the guidelines above followed regarding returning to work.

No one should be at work with active diarrhea.

Reported Incidence Is Higher than Usual/Outbreak Suspected

Consult with the epidemiologist on-call at CADE, (800) 362-2736. CADE can help determine a course of action to prevent further cases and can perform surveillance for cases that may cross several county lines and therefore may be difficult to identify at a local level.

If the number of reported cases in any city or county is higher than usual, or if an outbreak is suspected, investigate clustered cases in an area or institution to determine the source of infection and mode of transmission. A common vehicle (such as water, food or association with a child care center) should be sought and applicable preventive or control measures should be instituted. Control of person-to-person transmission requires special emphasis on personal cleanliness and sanitary disposal of feces.

Note: Refer to Iowa’s Foodborne Illness Outbreak Investigation Manual for comprehensive information on investigating foodborne illness complaints and outbreak.

D. Preventive Measures

Environmental Measures

Implicated food items must be removed from the environment. A decision about testing implicated food items can be made in consultation with the CADE. CADE can help coordinate pickup and testing of food samples. If a commercial product is suspected, CADE will coordinate follow-up with relevant outside agencies. If waterborne spread is suspected, contact the county environmental health office and IDPH Division of Environmental Health at (515) 281-7726.

• Environment, such as countertops and bathrooms should be cleaned with an EPA approved disinfectant.

• Follow recommended procedures for fecal coliform testing of recreational water supplies (e.g., pools, lakes).

The general practice of the SHL is to only test food samples implicated in suspected outbreaks; not single cases. The LPHA may suggest that the holders of food implicated in single case incidents locate a private laboratory, which will test food or store the food in their refrigerator for a period of time in case additional reports are received. Note: Refer to the Iowa’s Foodborne Illness Outbreak Investigation Manual for comprehensive information in investigating foodborne illness complaints and outbreak.

Preventive Measures/Education

To avoid exposure, advise individuals:

• To always wash their hands thoroughly with soap and water before eating or preparing food, after using the toilet and after changing diapers. (After changing diapers, wash the child’s hands also.)

• In all settings, especially child care, dispose of feces in a sanitary manner.
• When caring for someone with diarrhea, the care giver should wash their hands with plenty of soap and water after helping the person use the toilet, changing diapers, cleaning the bathroom, soiled clothes or soiled sheets. The patient’s hands should be washed also.

• Avoid sexual practices that may permit fecal-oral transmission. Latex barrier protection should be emphasized as a way to prevent the spread of E. coli  to a case’s sexual partners as well as being a way to prevent the exposure to and transmission of other pathogens.

• If diagnosed with pathogenic E. coli , seek medical attention if symptoms compatible with hemolytic uremic syndrome (HUS) occur. (See chapter on HUS.)
• Keep food that will be eaten raw, such as fruits and vegetables, from becoming contaminated by animal-derived food products. (Wash thoroughly, especially those that will not be cooked.)
• If served an undercooked hamburger or other ground beef product in a restaurant, send it back for further cooking.
• Cook all ground meats thoroughly.
• Drink only pasteurized milk, juice, or cider.

Iowa Dept. of Public Health, Revised 7-15