Abstract
Six Staphylococcus strains were isolated from healthy black bears (Ursus americanus) in the Great Smoky Mountains National Park, Tennessee, USA. Phylogenetic analysis based on complete genome, 16S rRNA, dnaJ, hsp60, rpoB and sodA genes, and MALDI-TOF-MS main spectral profiles revealed that the strains belonged to one species and showed the closest relatedness to members of the 'Staphylococcus intermedius group' (SIG), which include Staphylococcus intermedius, Staphylococcus pseudintermedius, Staphylococcus delphini and Staphyloccoccus cornubiensis. The strains were positive in SIG-specific and negative in individual species-specific PCR assays for the nuc gene. The strains can be differentiated from the other SIG species by the absence of sucrose fermentation, from S. intermedius DSM 20373(T), S. pseudintermedius CCUG 49543(T) and S. cornubiensis DSM 105366(T) by the absence of methyl β-d-glucopyranoside fermentation and from S. delphini DSM 20771(T) by fermentation of trehalose. DNA relatedness of the type strain MI 10-1553(T) with the type strains of S. delphini, S. pseudintermedius, S. intermedius and S. cornubiensis was ≤48.2 % by digital DNA-DNA hybridization and ≤92.3 % by average nucleotide identity calculations. Iso-(C15:0), anteiso-C(15 : 0) and anteiso-C(17 : 0) were the most common fatty acids. Polar lipids consisted of phosphadidylglycerols, phospholipids, glycolipid, diphosphatidylglycerol and aminophospholipid. Cell-wall peptidoglycan was of type A3α l-Lys-Gly(3) (Ser; similar to A11.2 and A11.3). The respiratory quinone belonged to menaquinone 7 (MK-7). The G+C content of MI 10-1553(T) was 39.3 mol%. The isolated strains represent a novel species of the genus Staphylococcus, for which we propose the name Staphylococcus ursi sp. nov. The type strain is MI 10-1553(T) (=ATCC TSD-55(T)=CCOS 1900(T)).