Escherichia coli (E. coli) are normal bacterial flora of the human gastrointestinal tract and can be classified by their O and H antigens. When these strains acquire certain genetic material, they can become pathogenic. Enterohemorrhagic Escherichia coli (EHEC) are strains capable of producing Shiga toxin, and are also referred to as Shiga–toxin producing E. coli or STEC, and sometimes called verocytotoxic E. coli (VTEC).
Since the initial recognition of severe bloody diarrhea due to E. coli O157:H7 infection in the United States in 1982, outbreaks and sporadic infections have been attributed to EHEC worldwide. After that, over 70 EHEC sereogroups have been isolated from ill patients, include O26, O111, O103, O45, O145 and O121. Cattle are the most important reservoir of STEC O157, other ruminants including sheep, goats and deer may carry STEC, too. People are infected mainly through ingestion of contaminated food or direct contact with animals or their environment. Human may serve as a source for person–to–person transmission.
The most effective protective measures are practicing good hand washing and food safety. Early recognition, supportive care and monitoring for the development of microangiopathic complications, such as hemolytic–uremic syndrome (HUS) can substantially lower the risk of medical complications and death.
EHEC infection is an important problem in North America, Europe, Japan, Australia, and the Southern Cone region of South America, however, it is not endemic in Taiwan. EHEC infection is one of the Category 2 communicable diseases in Taiwan. Clinicians report around 10-18 suspected cases per year, most of them were excluded. Over the years, there has only been one confirmed case in Taiwan, which was a 6-year-old child in 2001.
Figure.Number of EHEC Infections by Year– Taiwan, 2000-2018
EHEC Surveillance in Taiwan