Escherichia coli O157:H7 outbreak associated with consumption of ground beef, June-July 2002.
OBJECTIVE
A case-control and environmental study tested the hypothesis that purchasing and eating ground beef from a specific source was the cause of a cluster of cases of hemolytic uremic syndrome (HUS) and Escherichia coli (E. coli) O157:H7 gastroenteritis.


METHODS
A case-control study comparing risk factors was conducted over the telephone on nine case-patients with 23 selected controls. An environmental investigation was conducted that consisted of reviewing beef handling practices at a specific local supermarket and obtaining ground beef samples from the store and two households with case-patients.


RESULTS
The analysis of the case-control study showed that eight case-patients (89%) purchased ground beef at Grocery Chain A compared with four controls who did not develop illness (17%) (matched odds ratio=undefined; 95% confidence interval 2.8, infinity; p=0.006). The environmental investigation showed that Grocery Chain A received meat from Meatpacker A. Laboratory analysis of meat samples from Meatpacker A and Grocery Chain A and stool samples from some patients recovered an identical strain of E. coli O157:H7 according to pulse-field gel electrophoresis.


CONCLUSIONS
Both the case-control and environmental studies showed that purchasing ground beef at Grocery Chain A, which received ground beef from Meatpacker A, was the major risk factor for illness in eight case-patients; the ninth case-patient was found to be unrelated to the outbreak. Furthermore, meat from Meatpacker A was associated with a nationwide outbreak of E. coli O157:H7 illness that resulted in the second largest recall of beef in U.S. history at the time.
Vogt
Richard L
RL
Tri-County Health Department, Greenwood Village, CO 80111, USA. rvogt@tchd.org
Dippold
Laura
L
D000293:Adolescent; D000328:Adult; D000818:Animals; D016022:Case-Control Studies; D002417:Cattle; D002648:Child; D002675:Child, Preschool; D016000:Cluster Analysis; D015169:Colony Count, Microbial; D003120:Colorado / Q000453:epidemiology; D018563:Disease Notification; D004196:Disease Outbreaks / Q000706:statistics & numerical data*; D016521:Electrophoresis, Gel, Pulsed-Field; D004927:Escherichia coli Infections / Q000453:epidemiology* / Q000209:etiology; D019453:Escherichia coli O157; D005243:Feces / Q000382:microbiology; D005260:Female; D005506:Food Contamination / Q000706:statistics & numerical data; D005514:Food Irradiation; D005759:Gastroenteritis / Q000453:epidemiology* / Q000209:etiology; D006463:Hemolytic-Uremic Syndrome / Q000453:epidemiology* / Q000209:etiology; D006801:Humans; D008297:Male; D008460:Meat / Q000382:microbiology*; D008462:Meat-Packing Industry; D008875:Middle Aged; D011159:Population Surveillance; D015995:Prevalence; D015980:Public Health Practice; D012307:Risk Factors; D011795:Surveys and Questionnaires