Epidemiology and Infection

An outbreak due to peanuts in their shell caused by Salmonella enterica serotypes Stanley and Newport – sharing molecular information to solve international outbreaks

M. D. KIRK a1c1, C. L. LITTLE a2, M. LEM a3, M. FYFE a4, D. GENOBILE a5, A. TAN a6, J. THRELFALL a2, A. PACCAGNELLA a4, D. LIGHTFOOT a6, H. LYI a6, L. McINTYRE a4, L. WARD a2, D. J. BROWN a7, S. SURNAM a2 and I. S. T. FISHER a2
a1 Department of Health and Ageing, Food Safety & Surveillance Section, MDP 15, GPO Box 9848, Canberra City, Australian Capital Territory 2601, Australia
a2 Health Protection Agency, CDSC, 61 Colindale Avenue, London, NW9 5EQ, UK
a3 Community Medicine Residency Programme, Department of Health Care and Epidemiology, University of British Columbia, Ontario, Canada
a4 BC Centre for Disease Control, 655 W 12th Avenue, Vancouver, British Columbia, Canada V5Z 4R4
a5 Victorian Department of Human Services, 120 Spencer St. Melbourne 3000, Australia
a6 Microbiological Diagnostic Unit Public Health Laboratory, University of Melbourne, Parkville 3010, Australia
a7 Scottish Salmonella Reference Laboratory, Stobill Hospital, Glasgow G21 3UW, UK

Article author query
kirk m   [PubMed][Google Scholar] 
little c   [PubMed][Google Scholar] 
lem m   [PubMed][Google Scholar] 
fyfe m   [PubMed][Google Scholar] 
genobile d   [PubMed][Google Scholar] 
tan a   [PubMed][Google Scholar] 
threlfall j   [PubMed][Google Scholar] 
paccagnella a   [PubMed][Google Scholar] 
lightfoot d   [PubMed][Google Scholar] 
lyi h   [PubMed][Google Scholar] 
mcintyre l   [PubMed][Google Scholar] 
ward l   [PubMed][Google Scholar] 
brown d   [PubMed][Google Scholar] 
surnam s   [PubMed][Google Scholar] 
fisher i   [PubMed][Google Scholar] 


Salmonellosis is a global problem caused by the international movement of foods and high incidence in exporting countries. In September 2001, in an outbreak investigation Australia isolated Salmonella Stanley from imported peanuts, which resulted in a wider investigation in Canada, England & Wales and Scotland. Patients infected with Salmonella serotypes known to be isolated from peanuts and reported to surveillance systems were interviewed to determine exposure histories. Tagged image file format (TIFF) images of pulsed-field gel electrophoresis (PFGE) patterns of Salmonella isolates were shared electronically amongst laboratories. Laboratories tested packets of ‘Brand X’ peanuts from various lots and product lines. In total, 97 cases of S. Stanley and 12 cases of S. Newport infection were found. Seventy-three per cent (71/97) of S. Stanley cases were in persons of Asian ethnicity. Twenty-eight per cent of cases recalled eating Brand X peanuts and a further 13% had peanuts in their house in the previous month or had eaten Asian-style peanuts. Laboratories isolated S. Stanley, S. Newport, S. Kottbus, S. Lexington and S. Unnamed from Brand X peanuts. Isolates of S. Stanley from peanuts and human patients were indistinguishable by PFGE. This international outbreak resulted from a product originating from one country affecting several others. Rapid sharing of electronic DNA images was a crucial factor in delineating the outbreak; multinational investigations would benefit from a harmonized approach.

(Accepted January 15 2004)

c1 M. D. Kirk, Coordinating Epidemiologist, OzFoodNet, Department of Health and Ageing, Food Safety & Surveillance Section, MDP 15, GPO Box 9848, Canberra City, Australian Capital Territory 2601, Australia.