A long-lasting outbreak of Salmonella Typhimurium U323 associated with several pork products, Denmark, 2010

SUMMARY This paper shows that control of foodborne disease outbreaks may be challenging even after establishing the source of infection. An outbreak of Salmonella Typhimurium U323 infections occurred in Denmark from March to September 2010, involving 172 cases. Before the detection of human cases, several positive isolates of the outbreak strain had been found in a particular pig slaughterhouse and thus early traceback, investigation and control measures were possible. Several batches of pork and pork products were recalled and the slaughterhouse was closed twice for disinfection. No single common food item was identified as the outbreak source, but repeated isolation of the outbreak strain from the slaughterhouse environment and in pork and products as well as patient interviews strongly suggested different pork products as the source of infection. Furthermore, a matched case-control study identified a specific ready-to-eat spreadable pork sausage (teewurst) as the source of a sub-outbreak (matched odds ratio 17, 95% confidence interval 2·1–130).

[1]  Birgitte Borck Høg,et al.  DANMAP 2010: DANMAP 2010 - Use of antimicrobial agents and occurrence of antimicrobial resistance in bacteria from food animals, food and humans in Denmark , 2011 .

[2]  E. Nielsen,et al.  Phage typing of Salmonella Typhimurium - is it still a useful tool for surveillance and outbreak investigation? , 2010, Euro surveillance : bulletin Europeen sur les maladies transmissibles = European communicable disease bulletin.

[3]  T. Kantardjiev,et al.  Campylobacteriosis and other bacterial gastrointestinal diseases in Sofia, Bulgaria for the period 1987-2008. , 2010, Euro surveillance : bulletin Europeen sur les maladies transmissibles = European communicable disease bulletin.

[4]  E. Nielsen,et al.  Development of a new nomenclature for Salmonella typhimurium multilocus variable number of tandem repeats analysis (MLVA). , 2009, Euro surveillance : bulletin Europeen sur les maladies transmissibles = European communicable disease bulletin.

[5]  G. Nychas,et al.  Behavior of Escherichia coli O157:H7, Listeria monocytogenes, and Salmonella Typhimurium in teewurst, a raw spreadable sausage. , 2009, International journal of food microbiology.

[6]  S. Löfdahl,et al.  An outbreak of Salmonella Typhimurium infections in Denmark, Norway and Sweden, 2008. , 2009, Euro surveillance : bulletin Europeen sur les maladies transmissibles = European communicable disease bulletin.

[7]  K. Mølbak,et al.  Large outbreaks of Salmonella Typhimurium infection in Denmark in 2008. , 2008, Euro surveillance : bulletin Europeen sur les maladies transmissibles = European communicable disease bulletin.

[8]  D Harmsen,et al.  EUREGIO MRSA-net Twente/Münsterland--a Dutch-German cross-border network for the prevention and control of infections caused by methicillin-resistant Staphylococcus aureus. , 2008, Euro surveillance : bulletin Europeen sur les maladies transmissibles = European communicable disease bulletin.

[9]  R. Tauxe,et al.  Outbreak with multi-resistant Salmonella Typhimurium DT104 linked to carpaccio, Denmark, 2005 , 2007, Epidemiology and Infection.

[10]  E. Nielsen,et al.  Tandem Repeat Analysis for Surveillance of Human Salmonella Typhimurium Infections , 2007, Emerging infectious diseases.

[11]  L. Kreienbrock,et al.  Shiga toxin-producing Escherichia coli infection in Germany: different risk factors for different age groups. , 2006, American journal of epidemiology.

[12]  P. Mortensen,et al.  The Danish Civil Registration System. A cohort of eight million persons. , 2006, Danish medical bulletin.

[13]  S. Ethelberg,et al.  A regional outbreak of S. Typhimurium in Denmark and identification of the source using MLVA typing. , 2006, Euro surveillance : bulletin Europeen sur les maladies transmissibles = European communicable disease bulletin.

[14]  G. Kapperud,et al.  Multiple-locus variable-number tandem-repeats analysis of Salmonella enterica subsp. enterica serovar Typhimurium using PCR multiplexing and multicolor capillary electrophoresis. , 2004, Journal of microbiological methods.

[15]  Tine Hald,et al.  Salmonella Control Programs in Denmark , 2003, Emerging infectious diseases.

[16]  H. Karch,et al.  A large outbreak of hemolytic uremic syndrome caused by an unusual sorbitol-fermenting strain of Escherichia coli O157:H-. , 1999, The Journal of infectious diseases.

[17]  E. S. Anderson,et al.  Bacteriophage-typing designations of Salmonella typhimurium , 1977, Journal of Hygiene.

[18]  B. R. Callow.  A new phage-typing scheme for Salmonella typhi-murium , 1959, Journal of Hygiene.

[19]  L. Müller,et al.  Annual report on zoonoses in Denmark 2015 , 2005 .

[20]  T. Hald,et al.  Annual report on zoonoses in denmark 1997 , 1996 .

[21]  Agarwal Ds,et al.  An outbreak of Salmonella typhimurium infection in Delhi. , 1968, The Indian journal of medical research.