615. Epidemiology of Escherichia coli O157 foodborne outbreaks—United States, 2003–2008
Session: Poster Abstract Session: Outbreak Investigation
Friday, October 21, 2011
Room: Poster Hall B1
  • Heiman_IDSA2011_Epidemiology of E coli O157 outbreaks POSTER.pdf (342.2 kB)
  • Background: 

    E. coli O157 is estimated to cause more than 63,000 foodborne infections annually in the United States. Considerable efforts have been made to decrease E. coli contamination of foods, especially ground beef.  We reviewed foodborne disease outbreak surveillance data to assess the number and causes of outbreaks of E. coli O157 infections. 


    CDC defines a foodborne disease outbreak as two or more similar illnesses resulting from ingestion of a common food; and local, state, and territorial health departments report these to the CDC Foodborne Disease Outbreak Surveillance System (FDOSS) voluntarily.  We queried FDOSS for all outbreaks of E. coli O157 infections during 2003—2008.  Implicated foods were grouped into food commodities. We analyzed outbreak size and frequency, food commodities, and settings of food preparation.


    From 2003-2008, 165 outbreaks were reported, resulting in 2,501 illnesses, 711 hospitalizations, and 17 deaths. A median of 26 outbreaks occurred each year (range 18–41), increasing from a median of 20 per year from 2003–2005 to a median of 35 per year from 2006-2008. The number of outbreak-associated illnesses increased 129% between these two periods, from 761 in 2003–2005 to 1740 in 2006–2008.  Of the 84 outbreaks for which the food was known and belonged to a single commodity, the implicated commodities were beef (46 outbreaks, 55%), leafy vegetables (13 outbreaks, 15%), dairy (9 outbreaks, 10%, all unpasteurized), sprouts (4 outbreaks, 5%), game (4 outbreaks, 5%), and fruits-nuts (4 outbreaks, 5%).  Outbreaks attributed to leafy vegetables were larger than those attributed to beef (median number ill: 26 vs. 8, p<0.009), and most often involved food prepared in restaurants (50%).  Food was prepared at home in 64% of outbreaks attributed to beef compared with 10% of outbreaks attributed to leafy vegetables (p=0.003).

    Conclusion: The number of reported E. coli O157 outbreaks and illnesses increased during 2003–2008. Beef, leafy vegetables, and unpasteurized dairy products are common vehicles for E. coli O157 outbreaks. Outbreak characteristics, including number ill and settings of food preparation, differ between those attributed to beef and those attributed to leafy vegetables.

    Subject Category: N. Hospital-acquired and surgical infections, infection control, and health outcomes including general public health and health services research

    Katherine E. Heiman, MPH1, Shacara D. Johnson, MSPH1, Rajal K. Mody, MD, MPH1, Kristin G. Holt, DVM2, Alice Green, MS, DVM3, Patricia M. Griffin, MD1 and L. Hannah Gould, PhD1, (1)Centers for Disease Control and Prevention, Atlanta, GA, (2)USDA Food Safety and Inspection Service, Atlanta, GA, (3)USDA Food Safety and Inspection Service, Minneapolis, MN


    K. E. Heiman, None

    S. D. Johnson, None

    R. K. Mody, None

    K. G. Holt, None

    A. Green, None

    P. M. Griffin, None

    L. H. Gould, None

    Findings in the abstracts are embargoed until 12:01 a.m. EST Thursday, Oct. 20 with the exception of research findings presented at IDSA press conferences.