[Identification of Listeria using molecular DNA-DNA hybridization]

The DNA-DNA hybridization method was used to study 4 species of bacteria of the genus Listeria. Concerning the DNA homology, L. monocytogenes strains may be divided into several species (in particular, the pathogenic forms may be isolated into independent taxon), in correlation with their biochemical and serological properties. Most of the studied strains of this species exhibit a high level of DNA homology--65-100%. Bacteria of the L. grayi and L. murrayi species are closely related to each other (90% of DNA homology), the reasonable suggestion being to unite them into a single species. L. denitrificans has 7% of DNA homology with the DNA of the other three species suggesting that it should be excluded from the genus Listeria.