(225) Evaluation of Perioperative Antimicrobial Prophylaxis in Cardiac Surgery Patients

Introduction: Methicillin-resistant Staphylococcus aureus (MRSA) colonization and rates of MRSA surgical site infections (SSI) have decreased in recent years. Vancomycin is commonly used for perioperative prophylaxis despite higher rates of SSI and acute kidney injury (AKI) than cefazolin. The purpose of this comparative study is to help identify the preferred antimicrobial prophylaxis regimen in cardiac surgery.

Methods: This was a multicenter, retrospective descriptive analysis of clinical practice at two institutions. The electronic health record was utilized to identify adult patients admitted to either institution between January and December 2022 who were post-operative from coronary artery bypass graft (CABG) procedures. Patients were included if they were on a perioperative antibiotic regimen of either vancomycin and cefazolin or cefazolin monotherapy. Patients who received other antibiotic regimens were excluded. The primary outcome was the incidence of SSIs within 30 days of surgery. This was further categorized into superficial, deep, and organ/space according to NHSN definitions. Secondary outcomes included AKI defined by the the risk, injury, failure, loss, end-stage renal disease (RIFLE) criteria within 7 days of surgery , incidence of Clostridioides difficile infection within 90 days of surgery, in-hospital mortality, and hospital length of stay. Therapeutic antibiotics initiated after the prophylaxis window, defined as 48 hours to 90 days post-surgery, were also collected.

Results: A total of 1,061 patients were evaluated, resulting in the inclusion of 532 patients in the vancomycin and cefazolin cohort and 469 patients in the cefazolin monotherapy cohort. The incidence of SSIs within 30 days of the CABG procedure was significantly higher in the vancomycin and cefazolin cohort (10.4% vs 1.9%, p < 0.0001). All secondary outcomes were similar between cohorts.

Conclusions: Cefazolin monotherapy was associated with lower incidence of SSI within 30 days of surgery compared to vancomycin and cefazolin for surgical prophylaxis. This analysis helps identify a preferred antimicrobial prophylaxis regimen and is consistent with recent SHEA, IDSA, and APIC guidelines.