Preoperative Staphylococcus aureus screening and surgical site infection within 12 months after implant-based breast reconstruction: a real-world retrospective cohort study

Surgical site infections (SSIs) complicate implant-based breast reconstruction. Preoperative Staphylococcus aureus screening with targeted decolonisation is recommended in selected high-risk implant surgery, but its role in breast reconstruction remains unclear. This real-world retrospective cohort-included 1,535 implant-based breast reconstruction procedures at the Veneto Institute of Oncology–IRCCS (2020–2023). Preoperative nasal S. aureus screening, gradually implemented from 2022, was the primary exposure (screened vs. not screened). Targeted decolonisation was prescribed to carriers but was not analysed as a separate exposure. The primary outcome was SSI during extended, study-specific 12-month follow-up. Secondary analyses assessed 12-month readmission and colonisation–outcome associations among screened procedures. Cox proportional hazards models were used for time-to-event analysis. Screening was performed before 564 procedures (36.7%); 111/564 (19.7%) identified carriers. Twelve-month SSI incidence was 5.5% (85/1,535), declining from 8.7% in 2020 to 3.5% in 2023 ( p = 0.011); 78/85 (91.8%) occurred within 90 days. S. aureus was the most frequently identified pathogen (29/85, 34.1%). Screening was associated with a lower adjusted SSI hazard that was not statistically significant (adjHR 0.68, 95% CI 0.38–1.20; p = 0.183). Readmission occurred after 52 procedures (3.4%), mostly infection related. Older age (adjHR 1.03; p = 0.023), higher body mass index (adjHR 1.06; p = 0.009), and neoadjuvant therapy (adjHR 1.68; p = 0.049) were associated with higher SSI hazard. Tissue expander use was associated with a higher hazard of readmission (adjHR 2.08; p = 0.033) and showed a borderline association with a higher hazard of SSI (adjHR 1.67; p = 0.050). Conversely, expander-to-implant exchange was associated with a lower SSI hazard (adjHR 0.43; p = 0.030). Among screened procedures, nasal S. aureus colonisation was associated with a higher hazard of readmission (adjHR 3.04, 95% CI 1.01–9.11; p = 0.048). Preoperative S. aureus screening was not independently associated with significant SSI reduction; however, nasal carriage identified a subgroup at higher readmission risk. Implant-based breast reconstruction carried a non-negligible SSI risk varying by patient factors and reconstructive pathway, with greater vulnerability during tissue expander placement and lower-hazard after expander-to-implant exchange. Screening may support risk stratification, closer postoperative monitoring, and targeted perioperative prevention. Further studies should evaluate clinical effectiveness, organisational impact, and cost-effectiveness.