{ "abstract": "Background: Staphylococcus aureus is a leading cause of infection, and methicillin-resistant S. aureus (MRSA) is a high-priority resistance threat. MRSA and methicillin-susceptible S. aureus (MSSA) differ in non-β-lactam resistance, yet longitudinal data from Aseer, Saudi Arabia are limited. We characterized methicillin-resistance and non-susceptibility trends to inform local stewardship. Methods: We conducted a retrospective laboratory-based surveillance study of 4,194 S. aureus isolates from 3,122 patients (aged ≥12 years) at a tertiary-care center in Aseer, Saudi Arabia (January 2013–June 2024). Isolates were classified as MRSA or MSSA by oxacillin/cefoxitin testing to CLSI standards. We estimated annual non-susceptibility proportions and their temporal trends, compared non-susceptibility between MRSA and MSSA, and identified independent predictors of MRSA in a multivariable model accounting for repeated isolates from the same patient. Results: MRSA accounted for 2,231 isolates (53.2%; 95% CI 51.7–54.7) and MSSA for 1,963 (46.8%); most isolates were from inpatients, including 1,975/2,231 MRSA isolates (88.5%) and 1,648/1,963 MSSA isolates (84.0%). The MRSA share rose from 47.4% (2013) to 60.4% (2024), each later year being independently associated with MRSA (adjusted OR 1.09/year, 95% CI 1.06–1.12). MRSA was significantly more non-susceptible than MSSA to penicillin, ciprofloxacin, levofloxacin, erythromycin, clindamycin, gentamicin, trimethoprim–sulfamethoxazole, tetracycline, fusidic acid and rifampin (all FDR-adjusted p < 0.05), with the widest gap for fusidic acid (62.7% vs 25.0%); fusidic-acid and fluoroquinolone non-susceptibility also increased over time. No vancomycin or daptomycin non-susceptibility was detected; teicoplanin non-susceptibility was low but significantly higher in MRSA (2.8% vs 1.5%), and low-level linezolid non-susceptibility (1.5% vs 1.3%) was not confirmatory-tested. Conclusions: In this single-center Aseer surveillance, MRSA became the majority of S. aureus during 2013–2024 and showed broad multidrug non-susceptibility, while vancomycin and daptomycin retained full in vitro activity. These local findings support sustained laboratory-based surveillance, Aseer-tailored empirical and stewardship guidance, and confirmatory testing of the emerging low-level linezolid non-susceptibility signal.", "abstract_shown": true, "affiliations": [ "Department of Microbiology and Clinical Parasitology, College of Medicine, King Khalid University, Abha, Saudi Arabia", "Department of Medicine, Royal College of Surgeons, Dublin, Ireland", "Department of Family Medicine, Aseer Central Hospital, Abha, Saudi Arabia", "Department of Medicine, College of Medicine, King Khalid University, Abha, Saudi Arabia", "Department of Internal Medicine, Aseer Central Hospital, Abha, Saudi Arabia", "Department of Microbiology, Aseer Central Hospital, Abha, Saudi Arabia" ], "article_type": "Research Article", "arxiv": null, "author_total": 12, "authors": [ { "affs": [ 0 ], "name": "Abdulah J. Alqahtani" }, { "affs": [ 1 ], "name": "Yahya Shabi" }, { "affs": [ 2 ], "name": "Ghaday Hadi" }, { "affs": [ 3 ], "name": "Abdullah Algarni" }, { "affs": [ 4 ], "name": "Anandhalakshmi Subramanian" }, { "affs": [ 5 ], "name": "Ihab M. Abdelrahim" }, { "name": "Ali Al bshabshe" }, { "name": "Tarik Alazraqi" }, { "name": "Safia Abdullah Mohammed" }, { "name": "Sara Habbash" }, { "name": "Mona M. Alfaki" }, { "name": "Abdulah O. S. Bawazeer" } ], "bibtex": "https://research.draconitic.com/paper/0084sjr7zggg0.bib", "cited_by": 0, "doi": "10.1371/journal.pone.0357789", "fulltext_url": null, "id": "0084sjr7zggg0", "issns": [ "1932-6203" ], "landing_url": "https://doi.org/10.1371/journal.pone.0357789", "language": null, "licence": "CC-BY-4.0", "licence_label": "CC BY 4.0", "licence_source": "journal", "licence_url": "https://creativecommons.org/licenses/by/4.0/", "metadata_licence": null, "native_subjects": [ [ "openalex", "2725|Antimicrobial Resistance in Staphylococcus" ], [ "plos", "/Biology and life sciences/Microbiology/Medical microbiology/Microbial pathogens/Bacterial pathogens/Staphylococcus/Staphylococcus aureus" ], [ "plos", "/Biology and life sciences/Microbiology/Medical microbiology/Microbial pathogens/Bacterial pathogens/Staphylococcus/Staphylococcus aureus/Methicillin-resistant Staphylococcus aureus" ], [ "plos", "/Biology and life sciences/Microbiology/Microbial control/Antimicrobial resistance/Antibiotic resistance" ], [ "plos", "/Biology and life sciences/Microbiology/Microbial control/Antimicrobials/Antibiotics" ], [ "plos", "/Biology and life sciences/Microbiology/Microbial control/Antimicrobials/Antibiotics/Erythromycin" ], [ "plos", "/Biology and life sciences/Microbiology/Microbial control/Antimicrobials/Antibiotics/Tetracyclines" ], [ "plos", "/Biology and life sciences/Microbiology/Microbial control/Antimicrobials/Antibiotics/Vancomycin" ], [ "plos", "/Biology and life sciences/Organisms/Bacteria/Staphylococcus/Staphylococcus aureus" ], [ "plos", "/Biology and life sciences/Organisms/Bacteria/Staphylococcus/Staphylococcus aureus/Methicillin-resistant Staphylococcus aureus" ], [ "plos", "/Medicine and health sciences/Health care/Patients/Inpatients" ], [ "plos", "/Medicine and health sciences/Pathology and laboratory medicine/Pathogens/Microbial pathogens/Bacterial pathogens/Staphylococcus/Staphylococcus aureus" ], [ "plos", "/Medicine and health sciences/Pathology and laboratory medicine/Pathogens/Microbial pathogens/Bacterial pathogens/Staphylococcus/Staphylococcus aureus/Methicillin-resistant Staphylococcus aureus" ], [ "plos", "/Medicine and health sciences/Pharmacology/Antimicrobial resistance/Antibiotic resistance" ], [ "plos", "/Medicine and health sciences/Pharmacology/Drugs/Antimicrobials/Antibiotics" ], [ "plos", "/Medicine and health sciences/Pharmacology/Drugs/Antimicrobials/Antibiotics/Erythromycin" ], [ "plos", "/Medicine and health sciences/Pharmacology/Drugs/Antimicrobials/Antibiotics/Tetracyclines" ], [ "plos", "/Medicine and health sciences/Pharmacology/Drugs/Antimicrobials/Antibiotics/Vancomycin" ] ], "openalex": "W7213315687", "pdf_url": "https://journals.plos.org/plosone/article/file?id=10.1371/journal.pone.0357789&type=printable", "pmcid": null, "pmid": null, "published": "2026-09-15", "publisher": "Public Library of Science", "ris": "https://research.draconitic.com/paper/0084sjr7zggg0.ris", "sources": [ { "first_seen": "2026-10-30T12:17:49Z", "native_id": "10.1371/journal.pone.0357789", "source": "plos", "url": "https://doi.org/10.1371/journal.pone.0357789" } ], "subjects": [ { "field": "biology", "origin": "plos:microbiology", "subfield": "microbiology" }, { "field": "medicine", "origin": "plos:pharmacology", "subfield": "pharmacology-toxicology" } ], "title": "Methicillin resistance and antimicrobial non-susceptibility trends among Staphylococcus aureus clinical isolates in Aseer, Saudi Arabia (2013–2024): A retrospective laboratory-based surveillance study", "title_text": "Methicillin resistance and antimicrobial non-susceptibility trends among Staphylococcus aureus clinical isolates in Aseer, Saudi Arabia (2013–2024): A retrospective laboratory-based surveillance study", "type": "peer-reviewed", "updated_at": "2026-10-30T12:17:49Z", "url": "https://research.draconitic.com/paper/0084sjr7zggg0", "venue": "PLOS One", "versions": [] }