Molecular Epidemiology of Zoonotic Bacteria in the Food Chain in Luxembourg - EPIFOOD

Coordinating Institution: Laboratoire National de Santé
Contracting Partner(s): Administration des Services Techniques de l'Agriculture (ASTA) , Administration des Services Vétérinaires , Direction de la Santé, Luxembourg , European Center for Disease Control, Stockholm (S)
From: 01/07/2005
To: 30/06/2009
Budget: 849,400.00€
Contact(s): Mossong Joel

Summary

Food-borne bacterial gastrointestinal infections are not only associated with increased short-term and long-term risk of mortality but zoonotic food-borne outbreaks can incur substantial economic costs (BSE crisis, avian influenza). The aim of our project was to study presence of 4 of the most important foodborne bacterial pathogens (Salmonella, Campylobacter, verotoxigenic E. coli (VTEC), Listeria monocytogenes) at different levels of the food chain in Luxembourg and identify probable food sources and animal reservoirs linked to human illness.

This was achieved first of all by conducting prospective sampling of high risk food and veterinary matrices (feces, eggs, meat) at strategically important levels of the food chain (e.g. farm, slaughterhouse, super markets, butchers) in collaboration with the official food, veterinary and animal feed inspection institutions in Luxembourg. During our study over 3400 samples were collected from different levels of the food chain yielding a total of over 600 bacterial isolates.

Secondly, we implemented novel state-of-the-art discriminatory genotyping methods including pulsed field gel electrophoresis (PFGE), multi-locus sequence typing (MLST), multi locus variable number tandem repeat analysis (MLVA) and sequencing of verotoxins in our laboratory to be able to establish whether strains isolated in the food chain actually correspond to those found in human patients with clinical gastro-enteritis. The techniques we used are conceptually very similar genetic fingerprinting used for forensic purposes, except that for our purposes the “criminals” are bacteria instead of humans.

Of particular interest was a monophasic Salmonella enterica 4,[5],12:i:- strain which caused 2 major outbreaks of Salmonella infections in humans in Luxembourg involving over 140 laboratory confirmed salmonellosis cases including one death in the spring and summer of 2006. Our newly implemented molecular typing method and antibiotic resistance analysis has shown that the strain could be detected several months earlier than the outbreak in porcine feces obtained at a abattoir in Luxembourg and also in several pork meat samples taken during the height of the epidemic in two crèches and a butcher shop.

As such the results from the EPIFOOD project have been invaluable in helping to trace the source and identify pork as the probable source of infection during the epidemiological investigation. Furthermore our results suggest that Campylobacter jejuni and VTEC O157 can be frequently found at the primary production level in cattle, but it is less clear whether and how this translates to risk of food-borne infection in humans.

Refereed Scientific Publications
  • Multilocus sequence typing, pulsed-field gel electrophoresis, and fla short variable region typing of clonal complexes of Campylobacter jejuni strains of human, bovine, and poultry origins in Luxembourg. Ragimbeau C, Schneider F, Losch S, Even J, and Mossong J, Appl Environ Microbiol (Impact factor 3.801 in 2008), 2008. 74(24): p. 7715-22.
  • Outbreaks of monophasic Salmonella enterica serovar 4,[5],12:i:- in Luxembourg, Mossong J, Marques P, Ragimbeau C, Huberty-Krau P, Losch S, Meyer G, Moris G, Strottner C, Rabsch W, Schneider F. 2006. Euro Surveill. 2007 Jun 1;12(6):E11-2. http://www.eurosurveillance.org/ViewArticle.aspx?ArticleId=719.
  • Substantial reduction of human Salmonella Enteritidis infections in Luxembourg in 2005. Mossong J, Even J, Huberty-Krau P, Schneider F. Euro Surveill. 2006;11(3):pii=2879.
  • Molecular characterization and discriminatory abilities of genotyping methods of Campylobacter jejuni isolated from humans, chicken and cattle in Luxembourg. Mossong J, Ragimbeau C, Tapp J, Losch S, Meyer G, Even J, Schneider F. Zoonoses & Public Health 2007; 54 (s1): P073,39.
Other Publications
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