Staphylococcus saprophyticus subsp. bovis subsp. nov., Isolated from Bovine Nostrils

This article describes a newly identified coagulase-negative Staphylococcus subspecies isolated from bovine nostrils. Researchers studied five strains collected from healthy cows and classified them as Staphylococcus saprophyticus subsp. bovis based on comprehensive phenotypic, biochemical, genetic, and cell wall analyses. The strains were gram-positive, nonmotile cocci resistant to novobiocin but sensitive to lysostaphin. DNA-DNA hybridization revealed the five strains were genetically related to each other at 94-99% homology and to S. saprophyticus at 71% homology, confirming subspecies status. The new subspecies exhibits specific characteristics including nitrate reduction, acid production from ribose and glucose, and pyrrolidonyl arylamidase production. Cell wall analysis demonstrated Lys-Gly teichoic acid composition with glycine-serine ratios differing from S. saprophyticus subsp. saprophyticus. Fatty acid profiles showed predominant anteiso-C₁₅ branched-chain fatty acids. The type strain KV 12 (CCM 4410) had a DNA G+C content of 31.0 mol%. This taxonomic designation provides clear differentiation from related novobiocin-resistant staphylococci through multiple biochemical and molecular characteristics, facilitating accurate identification in clinical and environmental specimens.

Key findings

• A new subspecies, Staphylococcus saprophyticus subsp. bovis, was identified from five strains isolated from bovine nostrils in approximately 7% of healthy cows examined.
• DNA-DNA hybridization demonstrated the five strains were genetically homogeneous (94-99% relatedness) and related to S. saprophyticus at the subspecies level (71% relatedness) but not to other staphylococcal species.
• The subspecies is phenotypically distinguished from S. saprophyticus subsp. saprophyticus by smaller colony diameters, nitrate reduction, pyrrolidonyl arylamidase production, and fermentation of galactose and ribose.
• Cell wall peptidoglycan structure (Lys-Gly₃.₄₋₄.₀Ser₀.₂₋₀.₇) and fatty acid profiles containing high levels of anteiso-C₁₅ confirmed the taxonomic distinctness of the new subspecies.
• The type strain KV 12 (CCM 4410) exhibited universal susceptibility to common antibiotics including penicillin, gentamicin, and vancomycin, with variable resistance to tetracycline and certain beta-lactams among strains.