O2140: Do pre-operative antibiotics reduce surgical site infections in pediatric patients on therapeutic antibiotics for appendicitis? A multi-institutional prospective non-inferiority trial.

Background: Antibiotics administration within one hour of surgical incision is an established quality metric for reducing rates of surgical site infections. Recent data has called into question the necessity of giving an additional prophylactic dose of antibiotics to prevent surgical site infections in patients with acute intra-abdominal infections already receiving therapeutic antibiotics. Unnecessary administration of antibiotics can lead to antibiotic resistance and complications such as clostridium difficile infection or allergic reactions. We sought to investigate if treating patients with uncomplicated appendicitis with therapeutic antibiotics alone was non-inferior to treating with therapeutic and pre-operative prophylactic antibiotics in development of post-operative superficial skin infections (SSI).

Methods: A multi-institutional, prospective, non-inferiority trial was conducted at five children’s hospitals from June 2020 to March 2023. Pediatric patients < 18 years old with a preoperative diagnosis of uncomplicated appendicitis who received at least one dose of therapeutic antibiotics preoperatively were enrolled. Patients were subsequently excluded if their intraoperative diagnosis was not consistent with uncomplicated appendicitis. Patients were screened for administration of additional prophylactic doses of preoperative antibiotics given with 60 minutes of surgical incision. The primary outcome was development of an SSI within 30 days of surgery. Secondary outcomes included development of a deep space infection and clostridium difficile infection within 30 days of surgery. Categorical variables were assessed with chi-squared tests. Logistic regression assessed the relationship between various predictors and the primary outcome.

Results: 1416 eligible patients were enrolled. 212/1416 (15%) received preoperative prophylactic antibiotic in addition to therapeutic antibiotics within 1 hour of surgical incision. 22 patients developed the primary outcome (SSI), and there was no significant difference in the number of SSIs in the prophylactic antibiotic group compared to the therapeutic only antibiotic group (p=0.67). 3 patients (0.2%) developed clostridium difficile infections within 30 days of surgery and none had received prophylactic antibiotics (p=0.47). 24 patients developed deep space infections, but there was no significant difference between cohorts (p=0.36). The most common therapeutic antibiotic regimen given was ceftriaxone and metronidazole, and the most common prophylactic antibiotic given was cefazolin. There was no difference in length of stay or operative time between groups (p=0.95 and p=0.11, respectively). On multivariable logistic regression, no significant predictors of post-operative SSI were identified.

Conclusion: Giving an additional dose of preoperative prophylactic antibiotics to prevent SSI did not lead to a decreased rate of SSI in children with uncomplicated appendicitis already receiving therapeutic antibiotics. Based on these study results, we conclude that treating with therapeutic antibiotics alone is non-inferior to treating with therapeutic and prophylactic antibiotics in risk of developing a post-operative SSI in pediatric patients with uncomplicated appendicitis. Surgeons should consider withholding additional SSI-prophylaxis antibiotics in patients with uncomplicated appendicitis who have been given appropriate therapeutic antibiotics.