Epidemiology and Infection

Nationwide outbreak of listeriosis due to contaminated meat

P. S. MEAD a1c1 1 , E. F. DUNNE a1a2 1 , L. GRAVES a1 1 , M. WIEDMANN a3 1 , M. PATRICK a1 1 , S. HUNTER a1 1 , E. SALEHI a4 1 , F. MOSTASHARI a5 1 , A. CRAIG a6 1 , P. MSHAR a7 1 , T. BANNERMAN a4 1 , B. D. SAUDERS a8 1 , P. HAYES a1 1 , W. DEWITT a1 1 , P. SPARLING a10 1 , P. GRIFFIN a1 1 , D. MORSE a9 1 , L. SLUTSKER a1 1 and B. SWAMINATHAN a1 1
a1 Foodborne and Diarrheal Diseases Branch, Division of Bacterial and Mycotic Diseases, National Center for Infectious Diseases, Centers for Disease Control and Prevention, Atlanta, GA, USA
a2 Epidemiologic Intelligence Service, Epidemiology Program Office, Centers for Disease Control and Prevention, Atlanta, GA, USA
a3 Department of Food Science, Cornell University, Ithaca, New York, NY, USA
a4 Ohio Department of Health, Columbus, OH, USA
a5 Division of Epidemiology, New York City Department of Health, New York, NY, USA
a6 Tennessee Department of Health, Nashville, TN, USA
a7 Connecticut Department of Public Health, Hartford, CT, USA
a8 Wadsworth Center, New York State Department of Health, Albany, NY, USA
a9 Office of Science and Public Health, New York State Department of Health, Albany, NY, USA
a10 Food Safety and Inspection Service, United States Department of Agriculture, Atlanta, GA, USA

Article author query
mead ps   [PubMed][Google Scholar] 
dunne ef   [PubMed][Google Scholar] 
graves l   [PubMed][Google Scholar] 
wiedmann m   [PubMed][Google Scholar] 
patrick m   [PubMed][Google Scholar] 
hunter s   [PubMed][Google Scholar] 
salehi e   [PubMed][Google Scholar] 
mostashari f   [PubMed][Google Scholar] 
craig a   [PubMed][Google Scholar] 
mshar p   [PubMed][Google Scholar] 
bannerman t   [PubMed][Google Scholar] 
sauders bd   [PubMed][Google Scholar] 
hayes p   [PubMed][Google Scholar] 
dewitt w   [PubMed][Google Scholar] 
sparling p   [PubMed][Google Scholar] 
griffin p   [PubMed][Google Scholar] 
morse d   [PubMed][Google Scholar] 
slutsker l   [PubMed][Google Scholar] 
swaminathan b   [PubMed][Google Scholar] 


We used molecular subtyping to investigate an outbreak of listeriosis involving residents of 24 US states. We defined a case as infection with Listeria monocytogenes serotype 4b yielding one of several closely related patterns when subtyped by pulsed-field gel electrophoresis. Patients infected with strains yielding different patterns were used as controls. A total of 108 cases were identified with 14 associated deaths and four miscarriages or stillbirths. A case-control study implicated meat frankfurters as the likely source of infection (OR 17·3, 95% CI 2·4–160). The outbreak ended abruptly following a manufacturer-issued recall, and the outbreak strain was later detected in low levels in the recalled product. A second strain was recovered at higher levels but was not associated with human illness. Our findings suggest that L. monocytogenes strains vary widely in virulence and confirm that large outbreaks can occur even when only low levels of contamination are detected in sampled food. Standardized molecular subtyping and coordinated, multi-jurisdiction investigations can greatly facilitate detection and control of listeriosis outbreaks.

(Accepted August 12 2005)
(Published Online December 1 2005)

c1 Bacterial Zoonoses Branch, Centers for Disease Control and Prevention, PO Box 2087, Ft Collins CO, 80522, USA. (Email: pmead@cdc.gov)


1 for the Listeria Outbreak Working Group. Members of the Group are given in the Appendix.