Numerical classification and identification of some nocardioform bacteria.

Abstract

A total of 254 strains of the genera Nocardia, Rhodococcus, Amycolata, Amycolatopsis, Gordona and Pseudoamycolata were compared using numerical taxonomic techniques based on 273 physiological characters with the aid of miniaturized tests. Clustering was achieved using the unweighted pair group method with arithmetic averages (UPGMA) and the simple-matching coefficient (SSM) as the measure for similarity. Test error and overlap between the phena were within acceptable limits. Cluster groups were defined at the 87.4 to 91.3 % levels (SSM). A total of 25 clusters were obtained in the SSM/UPGMA analysis beside 16 single member clusters, which in most cases were marker strains of different species. For the 25 clusters, containing two or more strains, a matrix comprising frequencies for positive results of 35 tests was constructed. The minimum number of diagnostic characters was selected by computer programs (CHARSEP, DIACHAR, MOSTTYP). The final matrix consisting of 35 tests versus 25 phena was theoretically evaluated using a computer program (MATIDEN) and out of 238 strains, a total of 157 strains (65.96%) were correctly identified with a Willcox probability >0.999, further 18 strains (7.56%) achieved Willcox probabilities above 0.900 and 2 strains (0.84%) were identified correctly with a Willcox probability above 0.800. Correct identification results were obtained for a total of 56 strains (23.52%), but with low Willcox probabilities ranging between 0.500 and 0.800. A total of 5 strains (2.10%) could not be assigned to the correct phenon. In a subsequent practical evaluation of the matrix 32 of 40 tested strains (80.0%) were correctly identified with Willcox probabilities above 0.900.The genera Rhodococcus and Nocardia belong to the actinomycetes which are now largely defined on the basis of cell envelope lipids and peptidoglycan composition (8,40). The cell walls of representative nocardiae and rhodococci * Address reprint requests to: Dr . P. Kampfer, Fachgebiet Hygiene,

Application of miniaturized physiological tests in numerical classification and identification of some bacilli.

“…The hydrolysis of 42 chromogenic substrates, including glycosidase-, aminopeptidase-, phosphatase-, esterase-and sulphatasesubstrates was tested, in addition. Details about carbon source utilization tests and qualitative enzyme tests are described elsewhere (18). Sugar fermentation tests were done in the medium of Hugh and Leifson (16) Data analysis.…”

Transfer of Rhodococcus aichiensis Tsukamura 1982 and Nocardia amarae Lechevalier and Lechevalier 1974 to the Genus Gordona as Gordona aichiensis comb. nov. and Gordona amarae comb. nov.

“…In conclusion, the combined chemosystematic and phylogenetic data indicate that N amarae DSM 43392T and R. aichiensis DSM 4397ST are closely related to the genus Gor- ' The concentration used to determine raffinose utilization was 0.2% (wthol) (12).…”

Mycobacterium frederiksbergense sp. nov., a novel polycyclic aromatic hydrocarbon-degrading Mycobacterium species.

“…The protocols used to determine growth on xylose, trehalose, mannitol and sorbitol as sole sources of carbon were those of Silcox et al (1981). Additional carbon source utilization and quantitative enzyme tests were performed in standard microtitration plates (F-form, Greiner) as described by Ka$ mpfer et al (1990) with the following modifications : carbon source utilization test medium was yeast nitrogen base (Difco) supplemented with yeast extract (0n02 g l − "), K # HPO % (1n74 g l − ") and KH # PO % (0n36 g l − ") ; enzyme test medium contained 0n05 M Tris\HCl buffer, 0n05 % (w\v) Casamino acids (Difco) and 0n05 % (w\v) yeast extract (Difco). The panels were inoculated with a standardized bacterial suspension of 0n5-1n0 McFarlane units in 0n9% (w\v) NaCl and then incubated for 3 d at 28 mC.…”