A number of frequent acquired risk factors for listeriosis have been identified, such as pregnancy, diabetes, cancer, HIV infection, and immunosuppressive therapies. However, no genetic study on host susceptibility to listeriosis in humans has been performed so far, in the absence of prospective collection of patients' samples. Also, listeriosis diagnosis is based on Lm culture from clinical samples. This method lacks sensitivity, and the contribution of biomarkers to listeriosis diagnosis and prognosis has not been evaluated.