Primary prevention of surgical site infection: an antibiotic timing pilot

Authors:
Alicia C. Speak, Annmarie Vilkins, Arielle Gupta, Anita B Shallal, Trevor Szymanski, Abigail Ruby, Eman Chami

Body of Abstract:
Background:

Surgical site infections (SSI) are the most common complications of gynecologic procedures. Risk factors for SSI include surgical site, type and duration of surgery, and patient risk factors. Surgical infection prophylaxis (SIP) is a core strategy employed to reduce SSI, and the timing of antibiotics is of critical importance. Clinical guidelines recommend the use of cefazolin within 60 minutes of surgical incision. Following an observed increase in SSI standardized infection ratio (SIR) for gynecologic surgeries at our institution, a multi-disciplinary collaborative effort for antibiotic timing was introduced.

Methods:

This was an IRB exempt, single pre-test, post-test quasi-experiment at a single institution. All gynecologic cases between 1/1/2025-11/6/2025 requiring antibiotic prophylaxis per consensus guidelines were included. The intervention was introduced on 8/20/2025, where antibiotics were initiated on arrival to the operating room or at pre-induction time out if not already done. This was achieved through education roll-out to key stakeholders, including gynecology, anesthesia, and nursing teams. The primary endpoint was the timing of cefazolin SIP post-intervention, and secondary endpoint was the number of SSI cases post-intervention. A chi-square test of independence was conducted to examine the effect of the intervention on time to antibiotic administration, and Cramer’s V was calculated to measure the strength of association. “Ideal” antibiotic timing was defined as receiving antibiotics within 31-60 minutes pre-incision.

Results:

232 total cases were identified, including 183 pre-intervention and 44 post-intervention. There was a statistically significant difference in the number of patients who received ideal antibiotic timing for cefazolin in the post-intervention group (24; 54.4% compared to 43; 23.5% pre-intervention; p<0.005) [Figure 1]. In the pre-intervention group, 9 (4.92%) surgical site infections were identified, versus 0 (0.00%) in the post infection group. Conclusions: Improving the timing of SIP had a significant impact on our rates of SSI in gynecological operations, showing the importance of a multi-disciplinary approach on infection prevention in surgical patients. Following an educational roll-out with key stakeholders, antibiotics were significantly more likely to be given within an ideal timeframe. Our study is limited by the small number of post-intervention SSI, making interpretation difficult. There were also additional concomitant interventions (including re-training on appropriate scrub and abdominal preparation technique), that may confound these results and likely also contributed to decreased SSI rates.