CLINICAL DESCRIPTION

Escherichia coli O157:H7 bacteria produce potent cytotoxins called shiga toxins; clinical illness usually is a result of these toxins. Infection with E. coli O157:H7 may present with a wide spectrum of clinical manifestations. An individual may be asymptomatic, have mild non-bloody diarrhea, or have gross bloody diarrhea. Most diagnosed cases present with an onset of bloody diarrhea 6 to 48 hours after the onset of non-bloody diarrhea. Abdominal cramps, nausea and vomiting may also be present. Fever is usually absent. In severe cases, the patient may progress to develop hemolytic uremic syndrome (HUS) or thrombotic thrombocytopenic purpura (TTP), which can result in renal failure and death.The incubation period is variable, ranging from 2 to 8 days (or longer); most commonly the incubation is 3 to 4 days. Laboratory diagnosis is based upon isolation of E. coli O157:H7 from the feces or rectal swabs, demonstration of shiga-like toxin, serotyping tests or by identification of toxin genes or virulence plasmids.

CASE CLASSIFICATION

1. CONFIRMED

   A clinically compatible case AND
   

   • Isolation of E. coli O157:H7 from a specimen, OR
   • Isolation of Shiga toxin producing E. coli O157:H7 from a clinical specimen.
     
     

   
   

2. PROBABLE

   A case with isolation of E. coli O157 from a clinical specimen, pending confirmation of H7 antigen or Shiga toxin, OR a clinically compatible case that is epidemiologically linked to a NJDHSS laboratory-confirmed or probable case.

   
   

3. POSSIBLE
   
   Not used.

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