The Multicentric Observational NAtional Analysis of Listeriosis and Listeria (MONALISA), is the first national case-control prospective study on listeriosis. It is implemented since 2009 and enrolls all culture-proven cases declared to the NRCL: and collects for each patient clinical and biological data and biological samples. Controls with comparable background and presentation are also included. 818 cases have been included (427 S, 252 CNS and 107 MN) over 3.5 years, along with 456 controls.