{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,6,19]],"date-time":"2026-06-19T04:38:40Z","timestamp":1781843920618,"version":"3.54.5"},"reference-count":27,"publisher":"MDPI AG","issue":"8","license":[{"start":{"date-parts":[[2025,8,7]],"date-time":"2025-08-07T00:00:00Z","timestamp":1754524800000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Antibiotics"],"abstract":"<jats:p>Introduction: Borderline oxacillin-resistant Staphylococcus aureus (BORSA) represents a rare and poorly characterized phenotype of S. aureus. Its detection remains challenging, even in modern clinical laboratories. Moreover, there is no consensus on the optimal therapeutic approach, and treatment strategies remain controversial. In this report, we present a rare case of BORSA bacteremia and discuss potential approaches to improve its detection and management. Case presentation: A 39-year-old woman with systemic lupus erythematosus was admitted for a suspected exacerbation, complicated by multiple serositis and nephritis. She was on chronic treatment with methylprednisolone and hydroxychloroquine. On admission, she was afebrile. Laboratory investigations revealed elevated C-reactive protein and increased D-dimer levels. Later, she developed a septic peripheral venous thrombophlebitis, and treatment was adjusted to amoxicillin\u2013clavulanate. Blood cultures grew S. aureus, prompting a switch to intravenous oxacillin based on a negative penicillin-binding protein 2a test. A discrepancy in the antimicrobial susceptibility test was observed, with cefoxitin showing susceptibility and oxacillin resistance. Further characterizations were carried out, confirming a BORSA infection. Treatment was switched to linezolid and ciprofloxacin with good recovery. Conclusions: This case highlights the complexity of managing a patient with an uncommon and poorly documented infection. The lack of data on BORSA infections and the difficulties in detecting and treating them led to a prolonged delay in the appropriate management of this patient.<\/jats:p>","DOI":"10.3390\/antibiotics14080809","type":"journal-article","created":{"date-parts":[[2025,8,7]],"date-time":"2025-08-07T12:15:40Z","timestamp":1754568940000},"page":"809","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":3,"title":["Borderline Oxacillin-Resistant Staphylococcus aureus (BORSA) Bacteremia\u2014Case Report"],"prefix":"10.3390","volume":"14","author":[{"ORCID":"https:\/\/orcid.org\/0000-0001-5879-3072","authenticated-orcid":false,"given":"Beverly","family":"Buffart","sequence":"first","affiliation":[{"name":"Department of Microbiology, Laboratoire Hospitalier Universitaire de Bruxelles\u2014Universitair Laboratorium Brussel (LHUB-ULB), Universit\u00e9 Libre de Bruxelles (ULB), 1000 Brussels, Belgium"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Philippe","family":"Clevenbergh","sequence":"additional","affiliation":[{"name":"Infectious Diseases Department, University Hospital Brugmann, Universit\u00e9 Libre de Bruxelles (ULB), 1090 Brussels, Belgium"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Alina","family":"Stiuliuc","sequence":"additional","affiliation":[{"name":"Rhumatologic Diseases Department, University Hospital Brugmann, Universit\u00e9 Libre de Bruxelles (ULB), 1090 Brussels, Belgium"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Ioannis","family":"Raftakis","sequence":"additional","affiliation":[{"name":"Rhumatologic Diseases Department, University Hospital Brugmann, Universit\u00e9 Libre de Bruxelles (ULB), 1090 Brussels, Belgium"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Mony","family":"Hing","sequence":"additional","affiliation":[{"name":"Department of Microbiology, Laboratoire Hospitalier Universitaire de Bruxelles\u2014Universitair Laboratorium Brussel (LHUB-ULB), Universit\u00e9 Libre de Bruxelles (ULB), 1000 Brussels, Belgium"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"V\u00e9ronique Yvette","family":"Miendje Deyi","sequence":"additional","affiliation":[{"name":"Department of Microbiology, Laboratoire Hospitalier Universitaire de Bruxelles\u2014Universitair Laboratorium Brussel (LHUB-ULB), Universit\u00e9 Libre de Bruxelles (ULB), 1000 Brussels, Belgium"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Olivier","family":"Denis","sequence":"additional","affiliation":[{"name":"Department of Microbiology, Laboratoire Hospitalier Universitaire de Bruxelles\u2014Universitair Laboratorium Brussel (LHUB-ULB), Universit\u00e9 Libre de Bruxelles (ULB), 1000 Brussels, Belgium"},{"name":"Faculty of Medicine, Universit\u00e9 libre de Bruxelles (ULB), 1070 Brussels, Belgium"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-9307-7418","authenticated-orcid":false,"given":"Delphine","family":"Martiny","sequence":"additional","affiliation":[{"name":"Department of Microbiology, Laboratoire Hospitalier Universitaire de Bruxelles\u2014Universitair Laboratorium Brussel (LHUB-ULB), Universit\u00e9 Libre de Bruxelles (ULB), 1000 Brussels, Belgium"},{"name":"Faculty of Medicine and Pharmacy, University of Mons (UMONS), 7000 Mons, Belgium"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-1706-6869","authenticated-orcid":false,"given":"Nicolas","family":"Yin","sequence":"additional","affiliation":[{"name":"Department of Microbiology, Laboratoire Hospitalier Universitaire de Bruxelles\u2014Universitair Laboratorium Brussel (LHUB-ULB), Universit\u00e9 Libre de Bruxelles (ULB), 1000 Brussels, Belgium"},{"name":"National Reference Centre for <i>Staphylococcus aureus<\/i>, Laboratoire Hospitalier Universitaire de Bruxelles\u2014Universitair Laboratorium Brussel (LHUB-ULB), Universit\u00e9 Libre de Bruxelles, 1000 Brussels, Belgium"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1968","published-online":{"date-parts":[[2025,8,7]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"380","DOI":"10.1038\/s41579-023-00852-y","article-title":"Staphylococcus aureus host interactions and adaptation","volume":"21","author":"Howden","year":"2023","journal-title":"Nat. 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