Temporally Distinct Escherichia Coli 0157 Outbreaks Associated with Alfalfa Sprouts Linked to a Common Seed Source

Temporally distinct Escherichia coli 0157 outbreaks associated with alfalfa sprouts linked to a common seed source–Colorado and Minnesota, 2003.

Epidemiol Infect. 2005 Jun;133(3):439-47
Ferguson DD, Scheftel J, Cronquist A, Smith K, Woo-Ming A, Anderson E, Knutsen J, De AK, Gershman K.
Epidemic Intelligence Service, Colorado Department of Public Health and Environment, Denver, CO 80246, USA. dayna.ferguson@state.co.us

Escherichia coli O157 outbreaks were identified in Minnesota in February 2003involving seven persons and in Colorado in July 2003 involving 13 persons. Case isolates from the two states had matching pulsed-field gel electrophoresis (PFGE) patterns. Independent case-control studies linked infections in each outbreak with eating alfalfa sprouts that weretraced to the same seed distributor. The Colorado sprouter reportedly complied with the Food and Drug Administration (FDA) sprout guidance, whereas the Minnesota sprouter did not. These investigations revealed that increased compliance with existing FDA guidance is needed and that additional research is needed to improve the alfalfa seed decontamination process. This reaffirms the FDA recommendation that raw alfalfa sprouts should be considered potentially contaminated and avoided by persons at high-risk such as the elderly, young children, and immunocompromised persons. PFGE played an essential role in linking these two temporally and geographically distinct E. coli O157 outbreaks.