Staphylococcus agnetis sp. nov., a coagulase-variable species from bovine subclinical and mild clinical mastitis.

Thirteen Gram-positive-staining coagulase-variable staphylococci were isolated from subclinical and mild clinical mastitic bovine milk (n=12) and a teat apex (n=1). The results of sequence analysis of the 16S rRNA gene and two housekeeping genes, rpoB and tuf, and DNA fingerprinting with amplified fragment length polymorphism (AFLP) analysis showed that the isolates formed a separate branch within the genus Staphylococcus. The phylogenetically most closely related species were Staphylococcus hyicus and Staphylococcus chromogenes. DNA-DNA hybridization with S. hyicus DSM 20459(T) and S. chromogenes DSM 20674(T) confirmed that the isolates belonged to a separate species. The predominant fatty acids were i-C(15:0), ai-C(15:0), i-C(17:0) and C(20:0) and the peptidoglycan type was A3α L-Lys-Gly(5). Based on the results of genotypic and phenotypic analyses, it is proposed that the thirteen isolates represent a novel species, for which the name Staphylococcus agnetis sp. nov. is proposed. Strain 6-4(T) (=DSM 23656(T)=CCUG 59809(T)) is the type strain.