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Escherichia coli O157:H7 (E. coli O157:H7)
1996 Case Definition
Clinical description
An infection of variable severity characterized
by diarrhea (often bloody) and abdominal cramps. Illness may
be complicated by hemolytic uremic
syndrome (HUS) or thrombotic thrombocytopenic purpura (TTP);
asymptomatic infections also may occur.
Laboratory criteria for diagnosis
- Isolation of Escherichia coli O157:H7
from a specimen, or
- Isolation of Shiga toxin-producing E. coli O157:NM
from a clinical specimen*
Case classification
Suspect: A case
of postdiarrheal HUS or TTP (see HUS case definition)
Probable:
- A case with isolation of E. coli O157 from
a clinical specimen, pending confirmation of H7 or Shiga toxin
or
- A clinically compatible case that is epidemiologically
linked to a confirmed or probable case
Confirmed: A case that is laboratory confirmed.
Comment
Laboratory-confirmed isolates are reported via
the Public Health Laboratory Information System (PHLIS), which
is managed by the Foodborne and Diarrheal Diseases Branch, Division
of Bacterial and Mycotic Diseases, National Center for Infectious
Diseases, CDC. Both probable and confirmed cases are reported
to the National Notifiable Diseases Surveillance System (NNDSS),
but only confirmed cases are reported to PHLIS. Confirmation
is based on laboratory findings, and clinical illness is not
required.
*Strains of E. coli O157:H7 that have lost
the flagellar "H" antigen become nonmotile and are designated "NM"
See also:
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