Escherichia coli O157:H7
O157:H7, a Gram-negative bacillus, is a specific serotype of the shiga
toxin producing class of E. coli
(STEC) and the most common such serotype in the US.
Incubation period is 2-8 days. Shiga toxins cause
cramps and watery diarrhea,
often developing into bloody diarrhea; fever is uncommon. Likely modes of transmission
include foodborne (e.g., undercooked ground beef, fresh produce, unpasteurized juice,
raw milk) and person-to-person (e.g., day-care settings). There also have been
outbreaks associated with exposure to animals
and their environments
water exposure. All E.coli
O157:H7 isolates are confirmed by the Los
Public Health Laboratory.
Hemolytic uremic syndrome (HUS) is a clinical diagnosis and
may or may not be associated with E. coli
O157:H7. Children younger than
5 years of
age are at highest risk for hemolytic uremic syndrome (HUS), a clinical complication
consisting of hemolytic anemia, thrombocytopenia, and kidney failure. Adults may acquire
thrombotic thrombocytopenic purpura (TTP) after STEC infection.