Description of Arthrobacter creatinolyticus sp. nov., isolated from human urine.

Three strains of creatinine-hydrolysing bacteria isolated from human urine were characterized taxonomically. They were aerobic, non-spore-forming, Gram-positive rods with the peptidoglycan of the cell wall containing lysine. MK-8 and MK-9 were found to be the major types of menaquinone. The G + C content of the DNA was 66-67 mol%. The 16S rRNA sequence of one strain (GIFU 12498) was determined and aligned with other high-G + C-content Gram-positive rods from different genera. Following phylogenetic analysis, this strain was placed in the genus Arthrobacter. Arthrobacter protophormiae was the most closely related species in the phylogenetic tree, and this species also showed the highest sequence homology value (97%) with GIFU 12498. However, DNA-DNA hybridization indicated that GIFU 12498 did not belong to A. protophormiae (33.8 +/- 3.5% chromosomal similarity). The three urine strains belonged to one species because they shared more than 95% DNA-DNA similarity. It is proposed that these strains are placed in the genus Arthrobacter as a new species, Arthrobacter creatinolyticus sp. nov. The type strain of A. creatinolyticus is GIFU 12498, which has been deposited in the Japan Collection of Microorganisms (JCM) with the accession number JCM 10102.