ListAdapt: Adaptive traits of Listeria monocytogenes to its diverse ecological niches

The ListAdapt project aims were to decipher the molecular mechanisms of the adaptation of Lm to its various ecological niches by comparing  both genotypic and phenotypic data from a large and balanced set of strains from environment, animals, foods and clinical cases in several European countries.

The food-borne bacteria, Listeria monocytogenes (Lm), causing the disease of listeriosis, is together with Salmonella and STEC, the main causative agent for foodborne infections in EU, in terms of severity of the illness and fatality rate (EFSA-ECDC, 2015). It is a life-threatening disease because of the high mortality (20-30 %) and hospitalization (98.9 %) rates. A significant increase in the occurrence of listeriosis has been recorded since 2008 in Europe and this highlights listeriosis as a serious re-emerging health problem. In 2014, 2,161 confirmed human cases of listeriosis have been reported in Europe  ECDC atlas, EFSA-ECDC, 2015). However, the ecology of Lm is still poorly understood and 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.

To elucidate which genes and molecular mechanisms underlie the adaptation of Lm to its different ecological niches, ListAdapt used standard operating procedures (SOPs) for the production and analysis of Whole Genome Sequencing (WGS) data and bioinformatics tools previously developed for EU Horizon 2020-COMPARE project.

The ListAdapt consortium included 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 trained the others to COMPARE –SOPs and bioinformatics toolbox and stimulated them to use WGS for the surveillance of Lm in their country. This multidisciplinary project was found to 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.

The project has improved scientific knowledge on the ecology of the bacteria by gaining insight into the adaptation, evolution and genetic make-up of strains that are successful in some environmental niches and not in others. Furthermore, the project trained Reference Laboratories to use WGS using COMPARE-Standard Operating Procedures (SOPs) and encouraged them to use WGS for the surveillance of Lm in their country. Finally, the new diagnostic tests aimed at identifying strains in food and animal reservoirs have arisen from this project. These new tests should become key tools to improve the surveillance system, to assist the food industry in improving food safety and may have a significant economic impact and important benefit for society.

Project Outputs and Outcomes

Please read the project impact brochure, for more information on ListAdapt’s outputs and outcomes.

It is also available on Zenodo.