Raw Data to publication "<i>Staphylococcus borealis </i>-<i> </i>an emerging uropathogen of clinical relevance?"

Staphylococcus borealis is a recently described coagulase-negative staphylococcal species that remains poorly characterized with respect to its clinical relevance, pathogenic potential, and diagnostic differentiation from closely related species such as Staphylococcus haemolyticus. So far, only a single study has suggested a possible role of S. borealis as a uropathogen, and systematic clinical, phenotypic, and genomic data remain limited. In this study, we present a comprehensive analysis of 136 S. borealis isolates from hospitalized and non-hospitalized patients, compared to 100 S. haemolyticus isolates, integrating routine diagnostics, detailed phenotypic characterization, antimicrobial susceptibility testing, and whole-genome sequencing (WGS). Our findings highlight several clinically and microbiologically relevant aspects: · S. borealis isolates were predominantly recovered from middle-aged to elderly male hospitalized patients, many of whom had underlying conditions or were immunocompromised. · Repeated detection in semen samples from patients of the Andrology Department without overt infection, suggesting possible colonization or genital dysbiosis and raising questions regarding reproductive relevance. · Limited discriminatory power of routine diagnostics (MALDI-TOF MS and partial 16S rRNA sequencing) to reliably differentiate S. borealis from S. haemolyticus, underscoring the need for genomic confirmation and improved diagnostic strategies. · Detailed phenotypic and genomic characterization included pigmentation, urease production - including the identification of a putative sRNA-like element within the urease locus - biofilm formation, and antimicrobial resistance testing. Notably, biofilm-producing isolates lacked a complete ica (intercellular adhesion) operon, which is well known for Staphylococcus aureus and Staphylococcus epidermidis to confer polysaccharide-dependent biofilm formation. Interestingly, biofilm-positive S. borealis isolates formed predominantly proteinaceous rather than polysaccharide-based biofilms, indicating alternative biofilm mechanisms. Furthermore, we demonstrate that the yellow pigmentation observed in many isolates is genetically linked to an operon encoding enzymes homologous to the staphyloxanthin biosynthesis pathway described in S. aureus, suggesting potential implications for oxidative stress resistance and virulence. · Phylogenomic analyses further revealed that the human isolates form a distinct cluster separate from previously described bovine S. borealis isolates, supporting possible host-associated divergence. · A moderate multidrug resistance rate, lower than previously reported, with preserved susceptibility to vancomycin and linezolid. Importantly, our data indicate that S. borealis should no longer be regarded merely as a contaminant. The species exhibits characteristics consistent with urogenital colonization and potential pathogenicity, particularly in vulnerable patient populations. The recent differentiation from other coagulase-negative species, along with its previous frequent misidentification in routine diagnostics, may have contributed to its underrecognition in clinical practice to date. By combining clinical context, in-depth phenotypic assays, and WGS-based analyses, this study provides novel insights into diagnostic challenges, pigment-and urease- associated genetic determinants, biofilm production, and the potential clinical significance of this emerging staphylococcal species. We believe these findings will be of particular interest to clinicians, clinical microbiologists, infectious disease specialists, and researchers in urogenital and staphylococcal pathogenesis.