Chemotaxonomic studies were performed on some gram-positive coryneform bacteria of uncertain taxonomic position isolated from poultry deep litter. On the basis of the present chemical and previous phenetic studies, we suggest that these bacteria be classified in a new genus, Brachybacterium, as Brachybacterium faecium gen. nov., sp. nov. The type strain of Brachybacterium faecium is strain NCIB 9860.Schefferle (16) reported the isolation from poultry deep litter of a number of coryneform bacteria capable of degrading uric acid. Although the morphological, biochemical, and physiological characteristics of these strains were determined, their taxonomic position remained uncertain. Several of the isolates of Schefferle (16) were included in a numerical phenetic study by Jones (13) and were found to be related to Arthrobacter and Brevibacterium. However, three of the poultry isolates failed to cluster tightly with any recognized coryneform taxon although they did exhibit a "loose relationship" with Listeria denitrificans (13). The latter relationship was of particular interest as presently L . denitriJcans is represented by a single strain. Improvements in the classification of coryneform and related bacteria over the past decade have been almost entirely due to the application of chemotaxonomic methods. In particular, murein, nucleic acid, and lipid analyses have provided valuable criteria for distinguishing the major genera and for recognition of many new taxa (14) (see Table 3). Therefore, in this study we determined the chemical characteristics of the deep litter isolates mentioned above in an attempt to resolve their true taxonomic position. Our results indicate that these strains are closely related to each other but are quite distinct from all previously described coryneform taxa and warrant a new taxon, for which the name Brachybacterium faecium gen. nov., sp. nov. is proposed.
MATERIALS AND METHODSCultures and cultivation. For peptidoglycan and lipid studies the test strains (Table 1) were grown in shake cultures (10 g of tryptone, 5 g of yeast extract, 5 g of glucose, and 5 g of NaCl in 1 liter of water, pH 7.2) at 28°C and were harvested in the stationary phase by centrifugation. For deoxyribonucleic acid (DNA) work strains were cultivated on agar media and harvested in the late exponential phase.Peptidoglycan analysis. Walls were prepared from ca. 250 mg of dry cells by mechanical disruption with glass beads and were purified as described by Schleifer and Kandler (17). The amino acid compositions of complete wall hydrolysates were determined by using an automatic amino acid analyzer.DNA base composition determination. DNA was purified as described previously (12), and base composition was estimated by thermal denaturation in dilute saline citrate, using Escherichia coli NCDO 1984 as a standard.Analysis of fatty acids. Fatty acids were extracted from dry * Corresponding author.cells (50 mg) by acid methanolysis and were examined by gas-liquid chromatography as described previously (11). Analysis of isopre...