Introduction of integrated surveillance system of listeriosis in northern Italy (2012): molecular subtyping of human and food-environmental Listeria monocytogenes isolates

Human invasive listeriosis is a relatively rare (0.32 cases per year per 100,000 inhabitants in EU) but life threatening foodborne disease, with high hospitalization and fatality rates (>90% and 20-30% respectively) in vulnerable populations [1]. The aims of this study were to assess the molecular clustering of L. monocytogenes isolates by using pulsed-field gel electrophoresis (PFGE) and to evaluate phylogenetic correlation of human and food isolates in 2012 in Lombardy, the largest northern Italy region (about 10 million inhabitants), in order to activate an integrated laboratory-based surveillance network and strengthen the surveillance system of human listeriosis cases. This pilot study shows preliminary data in order to identify the main pulsotypes and the foods potentially involved in listeriosis cases in the Lombardy region. The results revealed the need to implement an integrated surveillance system, through the improvement of sampling criteria in foods of the whole area under study and strengthen the surveillance system of human cases.