[Comparative virulence of the 5 genomic groups of Listeria monocytogenes (sensu lato)].

Virulence of the five genomic groups of Listeria monocytogenes (sensu lato) was tested toward mice by determination of LD50 and growth or survival kinetics in vivo. Virulent strains included L. monocytogenes (sensu lato) (genomic group 1) and "L. bulgarica" (genomic group 2). The three other genomic groups, "L. innocua", "L. welshimeri" and "L. seeligeri", were apathogenic and avirulent under these experimental conditions.