Shiga Toxin Producing E. coli (STEC)

	Literature Recommendations
Exclusion-Case in SOS* (Symptomatic)	Yes [1-3,5-9,17] Grade III-A
Exclusion-Case in SOS* (Asymptomatic or previously symptomatic but now recovered)	Yes [7,16-17, 20] Grade III-A
Clearance-Case in SOS*	Yes [5,6, 7,8-9,11b, 12, 17,] 2 negative stool cultures taken 24 hours apart Grade III-A
Exclusion of Contact (Symptomatic)	Yes [1-3,5-9, 17] Grade III-A
Exclusion of Contact (Asymptomatic)	Specific recommendation to exclude asymptomatic contacts unavailable in literature reviewed [1]a
Exclusion-Case in Children (Group setting with children ≤ 5 years of age) (Symptomatic)	Yes [1,2,5-7,8,13,14,16,11] Grade II-A
Exclusion-Case in Children (Group setting with children ≤ 5 years of age) (Asymptomatic or previously symptomatic but now recovered)	Yes [1,13,16,17, 20] Grade III-A
◊ Applicable Code	None
* SOS (Sensitive Occupations or Situations) is not defined precisely in either the Code of Regulations or Health & Safety Code. See Attachment 2 for the definition of food workers. ◊ See California Code of Regulations, Attachment 1, for details. + Local health departments may elect to follow more restrictive exclusion and clearance criteria

a The Communicable Disease Report (1995) is a guideline which recommended clearance for asymptomatic contact [1]. Otherwise, literature was not identified which specifically mentioned asymptomatic contacts in reference to Shiga Toxin Producing Escherichia coli.
b Recommended 48 hours between stool cultures in outbreak setting with ongoing transmission.

Disease Trends in the U.S.:
From 1983-1987, an outbreak of E. coli 0157:H7 infection associated with hamburger occurred in a nursing home in Nebraska. This was the third reported foodborne outbreak due to this organism in the United States, the first two having occurred in 1982. Thirty-four persons were ill, 14 were hospitalized, and four died [23].
From 1996 through 1998, one outbreak of E. coli O157:H7 infection was associated with alfalfa or alfalfa clovers mixed sprouts; most of the patients were located in California. This outbreak along with five multistate outbreaks of Salmonella infectious associated with alfalfa sprouts, represented more than half of the outbreaks that occurred during that time in California and involved food vehicles confirmed by epidemiologic or laboratory data [14].
From 1995-1996, six outbreaks were caused by E. coli O157:H7. All of the outbreaks were associated with unchlorinated water or inadequately chlorinated water [24].
A review of STEC outbreaks from 1982 to 2002 reported the 350 outbreaks. Of these outbreaks, transmission routes for 183 were foodborne, 74 unknown, 50 person-to-person, 21 recreational water, 11 animal contacts, 10 from drinking water, and 1 laboratory-related transmission route [26].

In 1988 there were 68 cases of E coli O157:H7 in a span of 18 months. Twenty-nine of these cases occurred in 9 facilities and at each facility the index case had attended day care with active symptoms [11].

Between June and July of 2002, an outbreak associated with consumption of ground beef occurred. Case-control studies and environmental studies revealed that a meat packing company was responsible for the outbreaks across the United States [15].

Shiga Toxin Producing Escherichia coli (STEC) are diarrhea-causing bacteria that are pathogenic to humans. Infection may be asymptomatic; illness ranges from mild diarrhea to water or bloody diarrhea with severe diarrhea abdominal cramping and can result in hemolytic uremic syndrome (HUS)[22].

Organism: Shiga Toxin Producing Escherichia coli (STEC) O157:H7 is the main serotype in North America. Other serogroups in the United States include: O26, O111, O103, O45, and O121 [8]. E. coli is a gram-negative bacterium [10].

Reservoir of Infection: Cattle are the main reservoir of STEC; humans serve as reservoir in person-to-person transmission [8]. Outbreaks have been linked to ground beef, petting zoos, contaminated apple cider, raw fruits and vegetables, salami, yogurt, drinking water, and recreational water [4, 19, 21].
Mode of Transmission: Primarily through ingestion of food contaminated with feces. Person-to-person occurs among families, in childcare facilities and in custodial institutions. There is also waterborne transmission from contaminated drinking water and from recreational water [8, 11].
Attack Rates:
In the summer of 1998, an outbreak showed an attack rates among Alpine, Wyoming residents who drank Alpine municipal water were 23% during June 25 to July 1 and 27% during the 3-day period of June 26-28 [25].

The secondary attack rate in person-to-person outbreaks has ranged from 10% to 22%; this is particularly true among individuals in daycare centers and nursing homes [10].

 One study reported a 10.5% secondary attack rate of household contacts related to the index cases. The contacts presented with watery diarrhea. Siblings and grandparents of the index cases had the highest rate of STEC infection with 40% and 37.5 % respectively, whereas mothers had a 24% and fathers had a 5% rate of STEC infection [20].
Infectious Dose: Infectious dose of E. coli O157:H7 for humans is 10 to 100 organisms [10].
Incubation Period: Range = 2-10 days (median = 3-4 days) [8, 9].
Infectious Period: Duration of excretion is seven days or less in adults. In about 33% of children it may be 3 weeks; extended carriage is infrequent [8].
Asymptomatic Carrier State: longest carriage mentioned in reviewed articles was 62 days [11].
Diagnosis: Stool specimen cultured on sorbitol-MacConkey agar [18, 21].

Preventive Measures
Exclusions:
Symptomatic:

1. Multiple sources agree in recommending exclusions for symptomatic individuals, especially food handlers, child care providers, and health care workers, until 2 successive negative fecal samples collected in 24 hours or 48 hours following last dose of antimicrobials [5, 6, 8-9]. Guidelines and Consensus Document {Grade III-A}
2. According to Mohle-Boetani et al (2001)  “Almost all centers excluded children with diarrhea and/or vomiting, only one center did not excluded children with vomiting during less than three times per day; 33 (55.0%) required a note if the diarrhea was without blood, and 48 (80.0%) did so only if the diarrhea was bloody or mucinous. Forty-five centers (75.0%) required a physician’s note for children who vomited more than twice, and 27 (45.0%) for children who vomited once or twice” [14]. Review of Outbreaks and Epidemiology {Grade II-A} 
3. According to Bolyard et al (1998) “Restriction from patient care and the patient’s environment or from handling food is indicated for personnel with diarrhea or acute gastrointestinal symptoms regardless of causative agent” [3]. Evidence based reviews with guidelines formed out of reviewed literary sources {Grade III-A}
4. According to Heymann “Diarrheal illness in day-care attendees and employees should be managed carefully because of the high likelihood of person-to-person spread of common pathogens, such as E. coli O157:H7 and Shigella sonnei. Approaches to prevention and control of diarrheal disease in day-care setting have included requiring that ill children stay home, cohorting of convalescent children within the center and education of the community” [8 Guidelines and Consensus Document]. Guerrant et al (2001) state that, “Food-handlers and healthcare workers can transmit bacterial and parasitic diseases even if they are asymptomatic, it is recommended that before returning to their jobs these persons have 2 consecutive negative stools taken 24 hours apart and at least 48 hours after resolution of symptoms” [7 Evidence based reviews with guidelines formed out of reviewed literary sources]. Cases occurring in institutions should be isolated where practicable. Infectivity lasts for 48 hours after resolution of symptoms [2 Guidelines and Consensus Document]. The Communicable Disease Report (1995) states that Exclusion “48 after the first normal stool for cases not in the risk groups. Cases in risk groups 1 to 4 (Food handlers, Staff of healthcare facilities, children under the age of 5 and older children who may have problems implement proper personal hygiene) and contacts in risk groups 3 and 4 (children under the age of 5 and older children who may have problems implement proper personal hygiene) until clearance is obtained” [1]. Microbiological clearance for “risk groups 1 to 4 only—two negative faecal specimens taken at intervals not less than 48 hours apart” [1 Guidelines and Consensus Document]. {Grade III-A}
5. According to Belongia et al. (1993), in response to outbreaks of E coli O157: H7 in nine separate day-care facilities if they suspected ongoing transmission they “recommended that all children be excluded from day care until 2 serial cultures (48 hours apart) were negative [11].”   Review of Outbreaks and Epidemiology {Grade II-A}
6. According to Hashimoto et al (1999) “Re-examination of the stools for symptomatic subjects on days 26.0±5.4 after the first examination showed that 5 subjects, 4 of whom had received effective antibiotics, exhibited (E. coli O157:H7). These carriers were clinically healthy at the second stool culture” [12]. Review of Outbreaks and Epidemiology {Grade II-A}
7. Robinson (2001) states, “Exclusion of infected children from child care facilities is not necessary if toilet trained children and staff practice adequate handwashing. However, because it is not always the case, children who are suspected of having infectious diarrhea should be excluded from child care facilities” [13]. Guidelines and Consensus Document {Grade III-A}
8. According to Mohle-Boetani et al (2001) “In Israel, the Ministries of Education and Health stipulate that if the day-care center staff suspects that a child is ill, his/her parents or guardian must be notified immediately. If the child is suspected of having a communicable disease, he/she should be isolated according to regulations, even before parents are called” [14]. Review of Outbreaks and Epidemiology {Grade II-A}
9. According to Gouveia et al (1998), “shedding of viable organisms continued past the date when diarrhea ceased, and this should be taken into consideration when establishing criteria for readmission of children into day care. Cohorting of returning children that were previously symptomatic into a single room of the day care facility until two negative stools are obtained is a reasonable policy” [17] Review of Outbreaks and Epidemiology {Grade III-A}
10. According to Kahan et al (2005), “In Israel, the Ministries of Education and Health stipulate that if the day-care center staff suspects that a child is ill (term not specifically defined) his/her parents or guardian must be notified immediately. If the child is suspected of having a communicable disease, he/she should be isolated, according to regulations, even before the parents are called” [16]. Guidelines and Consensus Document (descriptive study) {Grade III-A}

Asymptomatic:

1. According to Robinson (2001), “asymptomatic carriers of Escherichia coli O157:H7 or Shigella should be excluded from child care facilities because spread of Shigella requires only a small number of organisms and infection with E. coli O157:H7 can result in sever sequelae” [13]. Guidelines and Consensus Document {Grade III-A}
2. According to Kahan et al (2005) “Asymptomatic carriers of Shigella or Escherichia coli 0157:H7 should be excluded because the spread of Shigella requires only a small number of organisms, and infection with E coli 0157:H7 may have severe sequelae” [16]. Guidelines and Consensus Document {Grade III-A}
3. Ludwig et al (2002) state, “While the number of HUS patients with infected household contacts varies in previously reported studies, depending on the study design and technique applied, it becomes apparent that STEC can be carried—and probably transmitted—by asymptomatic persons, albeit only for a brief period of time.” “Asymptomatic STEC infection in housed contacts represents a potential source of infection via person-to-person transmission” [20]. Review of Outbreaks and Epidemiology {Grade II-A}
4. According to Gouveia et al (1998), “shedding of viable organisms continued past the date when diarrhea ceased, and this should be taken into consideration when establishing criteria for readmission of children into day care. Cohorting of returning children that were previously symptomatic into a single room of the day care facility until two negative stools are obtained is a reasonable policy” [17]. Review of Outbreaks and Epidemiology {Grade III-A}
5. According to the Communicable Disease Report (1995) “Contacts in risk groups 1 to 4 (Food handlers, Staff of healthcare facilities, children under the age of 5 and older children who may have problems implement proper personal hygiene) should be screened microbiologically” [1]. Guerrant et al (2001) state that “Food-handlers and healthcare workers can transmit bacterial and parasitic diseases even if they are asymptomatic, it is recommended that before returning to their jobs these persons have 2 consecutive negative stools taken 24 hours apart and at least 48 hours after resolution of symptoms” [7]. Evidence based reviews with guidelines formed out of reviewed literary sources {Grade III-A}
6. Robinson (2001) “Asymptomatic carriers of Escherichia coli O157:H7 or Shigella should be excluded from child care facilities because spread of Shigella requires only a small number of organisms and infections with E. coli O157:H7 can result in severe sequelae” [13]. Guideline and Consensus Document {Grade III-A}

References

1. Communicable Disease Report Review. The Prevention of Human Transmission of Gastrointestinal infection, infestations, and bacterial infestrations. A Guide to Public Health Physicians and Environmental Health Officers in England and Wales.1995; Volume 5 Number 11: R158-172. Guidelines and Consensus Document
2. Public Health Laboratory Service, Advisory Committee on Gastrointestinal Infections. (2004). Preventing Person-to-Person Spread Following Gastrointestinal Infections: Guidelines for Public Health Physicians and Environmental Health Officers. Communicable Disease and Public Health , 7 (4), 362-384. Guidelines and Consensus Document
3. Bolyard EA, Ofelia CT, Water WW et al. (1998). Guidelines for Infection Control in Health Care Personnel. America Journal of Infectious Disease, 26(3), 307-308.  Evidence based reviews with guidelines formed out of reviewed literary sources
4. Dennehy, PH. (2005). Acute Diarrhea Disease in Children: Epidemiology, Prevention and Treatment. Infectious Disease Clinics of North America, 19, 582-602. Evidence Based Literature
5. APHA, AAP, & NRCHS. (2002). Exclusion and Inclusion of Ill Children in Child Care Facilities and Care of Ill Children in Child Care. Standards from CFOC, 2nd ed. Child Care Providers' Health and Well Being. Second Edition. A Joint Collaborative Project of The American Academy of Pediatrics, The American Public Health Association, and The National Resource Center for Health and Safety in Child Care.  Guidelines and Consensus Document
6. APHA, AAP and NRCHS. (2004). Child Care Provider's Health and Well Being. National Health and Safety Performance Standards: Guidelines for Out-of-Home Child Care. Second Edition. American Academy of Pediatrics, the American Public Health Association and the National REsoiurnce Center for Health and Safety in Child Care , 1-95.Guidelines and Consensus document
7. Guerrant RL, Van Gilder T, Steiner TS, et al. (2001). Practical Guideline for Management of Infectious Diarrhea. Clinical Infectious Diseases, 32, 331-350. Evidence based reviews with guidelines formed out of reviewed literary sources
8. Heymann, David. (2004). Control of Communicable Disease Manual 18th ed. Washington D.C.: American Public Health Association; 160-4. Guidelines and Consensus Document
9. United Kingdom’s Health Protection Agency. (n.d.). Guidelines on the Management of Communicable Diseases in School and Nurseries. Accessed at http://www.hpa.org.uk/infections/topics_az/school/schools.pdf. Guidelines and Consensus Document
10. Calderwook, SB.  (2007) Microbiology, pathogenesis and epidemiology of Enterohemorrhagic Escherichia coli. UpToDate.com, 1-8. Evidence Based Literature
11. Belongia EA, Osterholm MT, Soler JT et al. (1993). Transmission of Escherichia coli O127:H7 Infection in Minnesota Day-Care Facilites. Journal of American Medical Association, 269(7), 883-888. Review of Outbreaks and Epidemiology
12. Hashimoto H, Mizukoshi K, Nishi N et al. (1999). Epidemic of Gastrointestinal Tract Infection Including Hemorrhagic Colitis Attributable to Shiga Toxin 1-producing Escherichia coli O118:H2 at a Junior High School in Japan. Pediatrics, 103, 1-5. Review of Outbreaks and Epidemiology
13. Robinson, J. (2001). Infectious Diseases in Schools and Child Care Facilities. Pediatrics Review, 22, 39-47. Guidelines and Consensus Document
14. Mohle-Boetani J, Farrar J, Werner B et al. Escherichia coli O157:H7 and Salmonella Infection Associated with Sprouts in California, 1996-1998. Annals Internal Medicine, 135, 227-239. Review of Outbreaks and Epidemiology           
15. Vogt R and Dippold L. (2005). Escherichia coli O157:H7 Outbreak Associated with Consumption of Ground Beef, June-July 2002. Public Health Reports, 120, 174-178. Review of Outbreaks and Epidemiology
16. Kahan E, Gross S, and Cohen HA. (2005). Exclusion of Ill Children from child-care centers in Israel. Patient Education and Counseling, 56, 93-97. Guidelines and Consensus Document (Descriptive Study)
17. Gouveia S, Proctor ME, Lee MS et al. (1998). Genomic Comparisons and Shiga Toxin Production among Escherichia coli O157:H7 Isolates from a Day Care Center Outbreak and Sporadic Cases in Southeastern Wisconsin. Journal of Clinical Microbiology, 727-33. Review of Outbreaks and Epidemiology
18. Cieslak P, Noble S, Maxson D et al. (1997). Hamburger-Associated Escherichia coli O157:H7 Infection in Las Vegas: A Hidden Epidemic. American Journal of Public Health, 87 (2), 176-180. Review of Outbreaks and Epidemiology
19. Williams R, Isaacs S, Decou M et al. (2000).Illness outbreak associated with Escherichia coli O157:H7 in Genoa salami. CMAJ, 162(10), 1409-1413. Evidence Based Literature
20. Ludwig K, Sarkim V, Bitzan M et al. (2002). Shiga toxin-producing Escherichia coli infection and antibodies against Stx2 and Stx1 in household contacts of children with enteropathic hemolytic uremic syndrome. Journal of Clinical Microbiology, 1773-82. Review of Outbreaks and Epidemiology
21. Cody S, Glynn K, Farrar J et al. (1999). An outbreak of Escherichia coli O157:H7 infection from unpasteurized commercial apple juice. Annals of Internal Medicine, 130, 202-209. Review of Outbreaks and Epidemiology
22. Brooks J, Bergmire-Sweat D, Kennedy M et al (2004). Outbreak of Shiga Toxin-Producing Escherichia coli O111:H8 Infections among attendees of a high school cheerleading camp. Clinical Infectious Disease, 38, 190-198. Review of Outbreaks and Epidemiology
23. Bean NH, Griffin PM, Goulding JS et al. Foodborne Disease Outbreaks, 5-Year Summary, 1983-1987. Diseases Branch Division of Bacterial Diseases Center for Infectious Diseases Summary. Review of Outbreaks and Epidemiology
24.  Levy DA, Bens MS, Craun GF et al. Surveillance for Waterborne-Disease Outbreaks -- United States, 1995-1996. Morbidity and Mortality Weekly Report. Review of Outbreaks and Epidemiology
25. Olsen SJ, Miller G, Breuer T et al. (2002). A Waterborne Outbreak of Escherichia coli O157:H7 Infections and Hemolytic Uremic Syndrome: Implications for Rural Water Systems1. Emerging Infectious Diseases, 8(4), 370-375. Review of Outbreaks and Epidemiology
26. Rangel JM, Sparling PH, Crowe C et al. (2005), Epidemiology of Escherichia coli O157:H7 Outbreaks, United States, 1982–2002. Emerging Infectious Diseases, 11(4), 603-609. Review of Outbreaks and Epidemiology
27. Crump JA, Sulka A, Langer A et al. (2002). An Outbreak of Escherichia coli O175:H7 Infections among Visitors to a Dairy Farm. New England Journal of Medicine, 347(8), 555-560. Outbreak of Outbreaks and Epidemiology
28. Buetin L, Krause G, Zimmermann S et al. (2004). Characterization of Shiga Toxin-Producing Escherichia coli strains Isolated from Human Patients in Germany over a 3-year period. Journal of Clinical Microbiology, 1099-1108.  Evidence Based Literature

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