A Numerical Taxonomic Survey of Listeria and Related Bacteria

Abstract

A numerical taxonomic study was performed on named strains of Listeria, Erysipelothrix, Microbacterium thermosphactum, Lactobacillus, Streptococcus, Propionibacterium, Kurthia and some possibly related bacteria using 143 unit characters covering a wide range of properties. The strains fell into 6 main clusters: (A) Listeria; (B) M. thermosphactum, Lactobacillus, Streptococcus; (C) Gemella, Erysipelothrix; (D) Kurthia and mainly aerobic corynebacteria; (E) Propionibacterium, Staphylococcus; (F) mainly Cellulomonas. The genus Listeria contained 3 subgroups corresponding to L. monocytogenes, L. grayi and non-hemolytic listeria strains. L. murrayi did not appear to be sufficiently distinct from L. grayi to warrant separate species status. The genus Erysipelothrix was quite separate from the genus Listeria. M. thermosphactum was related to both the genera Listeria and Lactobacillus but formed a separate phenon that could appropriately be given generic rank. There were 4 distinct subgroups among the streptococci examined. Gemella strains appeared as a distinct phenon related to Erysipelothrix and the streptococci. The lactobacilli grouped into 4 phena largely corresponding to the subgenera Betabacterium, Streptobacterium and Thermobacterium and to the species Lactobacillus mali. Clusters A, B and C displayed a relatively close association to each other and it is recommended that all be included in the family Lactobacillaceae.