Comparative Genomics and Predictive Signature of Borderline Oxacillin-Resistant Staphylococcus aureus (BORSA) Detected at High Incidence during MRSA Surveillance in a Neonatal Intensive Care Unit

Here we report draft assemblies of 101 methicillin-resistant, -susceptible, and mec-negative borderline oxacillin-resistant Staphylococcus aureus isolates collected within one year at a midwestern US hospital. BORSA and MRSA isolates were primarily collected from the anterior nares of NICU infants during routine MRSA surveillance, while MSSA isolates were primarily taken from adult blood. Draft assemblies were used for comparative genomic analyses involving core and accessory genome similarity, and antibiotic-resistance gene content. Mutations within genes associated with oxacillin resistance were identified in all isolates and used as features along with beta-lactamase hyperproduction in a random forest classifier trained to predict borderline oxacillin resistant status among mec-negative S. aureus isolates.