The detection of the pathogenicity of Listeria using permanent cell lines as an alternative for animal studies

Culture filtrates of 38 strains of Listeria (L.) monocytogenes and of 4 strains of L. ivanovii were all cytotoxic for the vero cell line. Culture filtrates from 35 strains of L. innocua, 12 strains of L. seeligeri, 5 strains of L. welshimeri and 4 strains of L. grayi showed no cytotoxicity for the continuous cell line vero. The use of continuous cell lines permits to distinguish between pathogenic and non-pathogenic Listeria strains and seems to be a suitable method to replace the mouse pathogenicity test or the fertilized hen's eggs test.