The Multicentric Observational NAtional Analysis of Listeriosis and Listeria (MONALISA), a national case-control prospective study on listeriosis, was launched in 2009. It enrolls all culture-proven cases declared to the NRCL: clinical and biological data and biological samples (plasma, serum, PBMC) are collected at inclusion for each patient. 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.