Numerical Analysis of the Taxonomy of Nocardiae and Rhodococci

Abstract

The genera Nocardia and Rhodococcus were clearly differentiated in the present study. Eleven characteristics were shown to be useful for differentiation between these two genera. Nocardia asteroides sunsu stricto previously defined by Tsukamura was divided into two taxa. One contained the type strain and was considered to retain the name Nocardia asteroides in a new sense. Another was named in the present study as Nocardia nova sp. nov. Tsukamura. The type strain of this species is ATCC 33726. The following seven characters were useful for differentiating N. nova from newly defined N. asteroides: 1) arylsulfatase activity after 14 days; 2) catalase activity (semiquantitative); 3) β‐esterase activity; 4) pyrazinamidase activity; 5) utilization of citrate as a sole source of carbon; 6) utilization of 2,3‐butylene glycol as a sole carbon source; and 7) resistance to 5‐fluorouracil (20 μg/ml).The name Nocardia farcinica for Tsukamura's Kyoto‐I group should be rejected. This taxon has been named Nocardia paratuberculosis sp. nov. Tsukamura. The type strain is ATCC 23826.Three new species of the genus Rhodococcus were proposed: Rhodococcus aichiensis sp. nov. Tsukamura (type strain, ATCC 33611); Rhodococcus chubuensis sp. nov. Tsukamura (type strain, ATCC 33609); Rhodococcus obuensis sp. nov. Tsukamura (type strain, ATCC 33610).

Taxonomy, Physiology, and Natural Products of Actinobacteria

“…While the majority of nocardial infections have been attributed to Nocardia asteroides, other pathogenic Nocardia species that have been reported include N. brasiliensis, N. otitidiscaviarum, and N. transvalensis. In a taxonomic revision of the N. asteroides taxon, two new species, N. farcinica and Nocardia nova, were separated (495).…”

Nocardia abscessus sp. nov.

“…Numerous taxonomic studies have revealed the heterogeneity of the species Nocardia asteroides by using a variety of parameters, including numerical taxonomy (Gordon & Mihm, 1957 ;Kurup & Schmitt, 1973 ;Tsukamura, 1977Tsukamura, , 1982Schaal & Reuterberg, 1978 ;Orchard & Goodfellow, 1980), antigen-induced delayed hypersensitivity (Magnusson & Mariat, 1968), DNA homology (Franklin & McClung, 1976 ;Mordarski et al, 1978) and antimicrobial susceptibility (Wallace et al, 1988). Goodfellow & Lechevalier (1986) recognized three subgroups of N. asteroides.…”

Phylogeny of the Genus Nocardia Based on Reassessed 16S rRNA Gene Sequences Reveals Underspeciation and Division of Strains Classified as Nocardia asteroides into Three Established Species and Two Unnamed Taxons

“…Identification to the genus level is well established based on chemotaxonomic characteristics, mainly on the presence of a major amount of mesodiaminopimelic acid, arabinose, galactose, and mycolic acids with 46 to 60 carbons in cell walls (13,14). A variety of phenotypic characteristics for each Nocardia species can be found in the literature, but those of recently published species, such as N. abscessus and N. cyriacigeorgica (25, 26), have not been analyzed in collaborative numerical phenetic studies systematically in order to obtain a proposal of selected tests for routine identification of all medically relevant species (9,13,17,19,21). Studies of antimicrobial susceptibility revealed distinct drug pattern types within strains identified as N. asteroides, notably drug patterns I through VI (20).…”