A new aerobic, gram-positive, nonsporulating rod-shaped organism is described. Strain I F 0 15245T (T = type strain) has the following characteristics: the menaquinone contains a side chain with 11 isoprenyl units; the guanine-plus-cytosine content of the DNA is 66.2 mol%; 2,4-diaminobutyric acid, glutamic acid, alanine, glycine, and y-aminobutyric acid are present in the cell wall at a molar ratio of ca. 1:1:2:1:1; and glucose and galactose are also present in the cell wall. A comparison of partial 16s rRNA sequences revealed that I F 0 1524ST represents a distinct line of descent within the gram-positive bacteria with high guanine-plus-cytosine contents. The taxonomic characteristics of this organism are different from those of previously described aerobic, gram-positive, nonsporulating, rod-shaped bacteria. The name Leucobacter komagatae gen. nov., sp. nov., is proposed for this organism. The type strain is strain I F 0 15245.The following three genera of gram-positive, aerobic, irregular rods with 2,4-diaminobutyric acid (DAB) in their cell walls have been described previously: the genera Clavibacter (3), Rathayibacter (32), and Agromyces (33). Recently, the new genusAgrococcus (7), whose members also contain DAB in their peptidoglycans, has been proposed. These genera are differentiated by their menaquinone types, the compositions of their cell wall sugars, their DNA G+C contents, their pigmentation, and selected physiological features (1,3,4). The menaquinone found in the genus Clavibacter is MK-9, the menaquinone found 10 in the genus Rathayibacter is MK-10, the menaquinone found in the genus Agromyces is MK-12, and the menaquinones found in the genus Agrococcus are MK-11 and MK-12.Strain IF0 15245T (T = type strain), which was a contaminant in an ampoule labeled "Pseudomonas riboflavina" (18), is a gram-positive, nonmotile, rod-shaped organism. This strain has DAB in its cell wall, and its predominant menaquinone is MK-11. The presence of MK-11 reliably distinguishes strain I F 0 15245T from the members of the genera Agrococcus, Agromyces, Clavibacter, and Rathayibacter that have been described, but the taxonomic position of strain I F 0 15245T has remained uncertain. To clarify the taxonomic position of this organism and its intergeneric relationships with the previously described gram-positive, high-G + C-content bacteria, we determined a partial 16s rRNA sequence of I F 0 15245T and compared it with sequences of 20 representative actinobacteria and related organisms (1 1).In this paper, we describe the taxonomic features of strain I F 0 15245T, and on the basis of morphological, physiological, and chemotaxonomic characteristics and 16s rRNA sequence analysis data we propose that this organism should be classified in the new genus Leucobacter, as Leucobacter komagatae gen. nov., sp. nov.
MATERIALS AND METHODSBacterial strains and culture conditions. Strain IF0 15245= was isolated as a contaminant in an ampoule labeled "P. rihofluvina" IF0 13584, which was recently reidentified as Devosiu ribofluvina (...