Molecular epidemiology and evolution of virulence in the genus Listeria

The collaborative research project as intended by the applicant and the Grupo Patogenesis Molecular Bacteriana at the Facultad Veterinaria, Universidad Complutense, Madrid will focuse on the molecular structure of non-virulent, low- and high virulent, epidemiogenic strains of Listeria monocytogenes and how their pathogenic potential may correlate with epidemiological data. The partner institution is an excellent research unit which is internationally well known for its research on virulence and pathogenicity in the human pathogen Listeria monocytogenes. This group is also partner in a leading European network dealing with that topic. Occurrence of Listeria monocytogenes in food has an enormous relevance for food hygiene and food industry, as current food regulations consider any L. monocytogenes isolate to be potentially hazardous for human health. Thus, the "zero" tolerance criterion is widely applied concerning Listeria and food safety. However, epidemiological surveys proved only a small number of closely related Listeria monocytogenes subclones as cause of Listeria epidemics which occurred throughout the world during the last decade. Thus, the detection of Listeria contamination in food causes heavy economic losses to the food industry, although many food products that are replaced from the market by the health administration, yet Listeria-contaminated, probably do not represent a risk to the consumer. lt is the the aim of this project is to study the genetic diversity and population structure in pathogenic Listeria, and to understand the genetic relationships and virulence gene configuration in virulent and non-virulent isolates of different origins and characteristics. As a general long-term goal, this project is directed towards the definition of a series of molecular probes which will be useful to predict the pathogenic potential of foodborne L. monocytogenes isolates.