Listeria monocytogenes (Lm) is a ubiquitous bacterium that causes foodborne illness, listeriosis. This bacterium is the primary cause of mortality among foodborne diseases. The capacity of some strains to adapt to the environmental conditions found in the food industry makes production of high quality, safe food a major challenge. Lm can be found in outdoor environments, farm environments, vegetation, animals, water, sewage and food-processing environments. Lm is a paradigm for studying environmental adaptation of pathogenic bacteria. However, the ecology of Lm is still poorly understood. Many studies have highlighted the high genetic diversity within this species and demonstrated that some clonal complexes may be highly adapted to specific ecological niches: food, human, animals, and environment.
The project “Listadapt” aims to elucidate which genes and molecular mechanisms underlie adaptation of Listeria monocytogenes to its different ecological niches. We use the combination of Next Generation Sequencing (NGS) technology and phenotypical methodologies to compare data from a large and balanced set of strains from environment, animals, foods and clinical cases in several European countries.
Partners in this consortium include the European Union Reference laboratory (EURL) for Lm, 7 National Reference Laboratories (NRL) for Lm of which two also are National Public Health Laboratories and the EURL for antimicrobial resistance. The NRLs expert in WGS will train the others to bioinformatics toolbox and will stimulate them to use WGS for the surveillance of Lm in their country. This multidisciplinary project will benefit from the (i) expertise of partners in food safety as well as animal and public health, (ii) high- level infrastructures and (iii) 9000 strains already available within the consortium of which 2000 are whole sequenced. New molecular tests for detecting Lm strains in food, animal and clinical sectors may arise from this project, with important impact for laboratories involved in the surveillance of Lm.
Listadapt project relies on five main tasks. In the first a unique collection of strains related to environment and farms will be gathered. Then these strains will be sequenced. In the third step, a subset of the 200 strains will be compared with various phenotypic tests (biofilm, behavior in soil, biocide resistance, …). Finally, based on the sequences, phenotypes, metadata related to context of isolation of the strains, Genome Wide Association methods will be applied to determine adaptation markers of L. monocytogenes to its different ecological niches.We expect to uncover key molecular factors that may contribute to ability of Lm to colonize particular environments. These factors could explain why clonal complexes are successful in a given environment and unsuccessful in another.