Applied and Environmental Microbiology, November 2008, p. 6483-6494, Vol. 74, No. 21
0099-2240/08/$08.00+0 doi:10.1128/AEM.01129-08
Copyright © 2008, American Society for Microbiology. All Rights Reserved.
Broiler Campylobacter Contamination and Human Campylobacteriosis in Iceland 
,
Kenneth A. Callicott,1,
Hjördís Harðardóttir,2
Franklín Georgsson,3
Jarle Reiersen,4
Vala Friðriksdóttir,5
Eggert Gunnarsson,5
Pascal Michel,7
Jean-Robert Bisaillon,6
Karl G. Kristinsson,2
Haraldur Briem,8
Kelli L. Hiett,1
David S. Needleman,9 and
Norman J. Stern1*
Poultry Microbiological Safety Research Unit, USDA-ARS, Athens, Georgia,1 Landspitali National University Hospital, Reykjavik, Iceland,2 Food Laboratory, The Environmental & Food Agency, Reykjavik, Iceland,3 Reykjagarður, Reykjavik, Iceland,4 Institute of Experimental Pathology, Reykjavik, Iceland,5 Canadian Food Inspection Agency, Ottawa, Ontario, Canada,6 Laboratory for Foodborne Zoonoses, Public Health Agency of Canada, St. Hyacinthe, Quebec, Canada,7 Directorate of Health, Reykjavik, Iceland,8 Integrated Biomolecular Resources, ARS-USDA, Philadelphia, Pennsylvania9
Received 19 May 2008/ Accepted 21 August 2008
To examine whether there is a relationship between the degree of Campylobacter contamination observed in product lots of retail Icelandic broiler chicken carcasses and the incidence of human disease, 1,617 isolates from 327 individual product lots were genetically matched (using the flaA short variable region [SVR[) to 289 isolates from cases of human campylobacteriosis whose onset was within approximately 2 weeks from the date of processing. When there was genetic identity between broiler isolates and human isolates within the appropriate time frame, a retail product lot was classified as implicated in human disease. According to the results of this analysis, there were multiple clusters of human disease linked to the same process lot or lots. Implicated and nonimplicated retail product lots were compared for four lot descriptors: lot size, prevalence, mean contamination, and maximum contamination (as characterized by direct rinse plating). For retail product distributed fresh, Mann-Whitney U tests showed that implicated product lots had significantly (P = 0.0055) higher mean contamination than nonimplicated lots. The corresponding median values were 3.56 log CFU/carcass for implicated lots and 2.72 log CFU/carcass for nonimplicated lots. For frozen retail product, implicated lots were significantly (P = 0.0281) larger than nonimplicated lots. When the time frame was removed, retail product lots containing Campylobacter flaA SVR genotypes also seen in human disease had significantly higher mean and maximum contamination numbers than lots containing no genotypes seen in human disease for both fresh and frozen product. Our results suggest that cases of broiler-borne campylobacteriosis may occur in clusters and that the differences in mean contamination levels may provide a basis for regulatory action that is more specific than a presence-absence standard.
* Corresponding author. Mailing address: Poultry Microbiological Safety Research Unit, 950 College Station Road, Athens, GA 30605. Phone: (706) 546-3516. Fax: (706) 546-3771. E-mail: norman.stern{at}ars.usda.gov
Published ahead of print on 12 September 2008.
Supplemental material for this article may be found at http://aem.asm.org/.
Present address: USDA-ARS, Department of Plant Sciences, The University of Arizona, Tucson, AZ 85721.
Applied and Environmental Microbiology, November 2008, p. 6483-6494, Vol. 74, No. 21
0099-2240/08/$08.00+0 doi:10.1128/AEM.01129-08
Copyright © 2008, American Society for Microbiology. All Rights Reserved.
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