Methicillin resistance and antimicrobial non-susceptibility trends among Staphylococcus aureus clinical isolates in Aseer, Saudi Arabia (2013–2024): A retrospective laboratory-based surveillance study

@article{alqahtani2026methicillin,
  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}},
  author = {Abdulah J. Alqahtani and Yahya Shabi and Ghaday Hadi and Abdullah Algarni and Anandhalakshmi Subramanian and Ihab M. Abdelrahim and Ali Al bshabshe and Tarik Alazraqi and Safia Abdullah Mohammed and Sara Habbash and Mona M. Alfaki and Abdulah O. S. Bawazeer},
  journal = {PLOS One},
  year = {2026},
  month = sep,
  doi = {10.1371/journal.pone.0357789},
  url = {https://doi.org/10.1371/journal.pone.0357789},
  note = {CC BY 4.0},
}

TY  - JOUR
TI  - Methicillin resistance and antimicrobial non-susceptibility trends among Staphylococcus aureus clinical isolates in Aseer, Saudi Arabia (2013–2024): A retrospective laboratory-based surveillance study
AU  - Abdulah J. Alqahtani
AU  - Yahya Shabi
AU  - Ghaday Hadi
AU  - Abdullah Algarni
AU  - Anandhalakshmi Subramanian
AU  - Ihab M. Abdelrahim
AU  - Ali Al bshabshe
AU  - Tarik Alazraqi
AU  - Safia Abdullah Mohammed
AU  - Sara Habbash
AU  - Mona M. Alfaki
AU  - Abdulah O. S. Bawazeer
PY  - 2026
DA  - 2026/09/15
JO  - PLOS One
DO  - 10.1371/journal.pone.0357789
UR  - https://doi.org/10.1371/journal.pone.0357789
AB  - 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.
SN  - 1932-6203
ER  -