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U.S.
Food & Drug Administration Center for Food Safety & Applied Nutrition Foodborne Pathogenic Microorganisms and Natural Toxins Handbook |
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Enteropathogenic Escherichia coli
| 1. Name of the Organism:
Enteropathogenic Escherichia coli (EPEC) |
Currently, there are four recognized classes of enterovirulent E. coli (collectively referred to as the EEC group) that cause gastroenteritis in humans. Among these are the enteropathogenic (EPEC) strains. EPEC are defined as E. coli belonging to serogroups epidemiologically implicated as pathogens but whose virulence mechanism is unrelated to the excretion of typical E. coli enterotoxins. E. coli are Gram-negative, rod-shaped bacteria belonging the family Enterobacteriaceae. Source(s) and prevalence of EPEC are controversial because foodborne outbreaks are sporadic. Humans, bovines, and swine can be infected, and the latter often serve as common experimental animal models. E. coli are present in the normal gut flora of these mammals. The proportion of pathogenic to nonpathogenic strains, although the subject of intense research, is unknown. |
| 2. Nature of Acute Disease: | Infantile diarrhea is the name of the disease usually associated with EPEC. |
| 3. Nature of Disease: | EPEC cause either a watery or bloody
diarrhea, the former associated with the attachment to,
and physical alteration of, the integrity of the
intestine. Bloody diarrhea is associated with attachment
and an acute tissue-destructive process, perhaps caused
by a toxin similar to that of Shigella
dysenteriae, also called verotoxin. In most of
these strains the shiga-like toxin is cell-associated
rather than excreted. Infective dose -- EPEC are highly infectious for infants and the dose is presumably very low. In the few documented cases of adult diseases, the dose is presumably similar to other colonizers (greater than 10^6 total dose). |
| 4. Diagnosis of Human Illness: | The distinction of EPEC from other groups of pathogenic E. coli isolated from patients' stools involves serological and cell culture assays. Serotyping, although useful, is not strict for EPEC. |
| 5. Associated Foods: | Common foods implicated in EPEC outbreaks are raw beef and chicken, although any food exposed to fecal contamination is strongly suspect. |
| 6. Relative Frequency of Disease: | Outbreaks of EPEC are sporadic. Incidence varies on a worldwide basis; countries with poor sanitation practices have the most frequent outbreaks. |
| 7. Course of Disease and Complications: | Occasionally, diarrhea in infants is prolonged, leading to dehydration, electrolyte imbalance and death (50% mortality rates have been reported in third world countries). |
| 8. Target Populations: | EPEC outbreaks most often affect infants, especially those that are bottle fed, suggesting that contaminated water is often used to rehydrate infant formulae in underdeveloped countries. |
| 9. Food Analysis: | The isolation and identification of E. coli in foods follows standard enrichment and biochemical procedures. Serotyping of isolates to distinguish EPEC is laborious and requires high quality, specific antisera, and technical expertise. The total analysis may require from 7 to 14 days. |
| 10. Selected Outbreaks: | Literature references can be found at the links below. |
| Sporadic outbreaks of EPEC diarrhea have occurred for half a century in infant nurseries, presumably derived from the hospital environment or contaminated infant formula. Common-source outbreaks of EPEC diarrhea involving healthy young adults were reported in the late 1960s. Presumably a large inoculum was ingested. | |
| Morbidity and Mortality Weekly Reports | For more information on recent outbreaks see the CDC. |
| 11. Education and Background Resources: | None currently available. |
| 12. Molecular Structural Data: | None currently available. |
mow@cfsan.fda.gov
January 1992 with periodic updates
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