Comparison of Cefazolin/Metronidazole to Ampicillin/Sulbactam as Preoperative Antibiotics in Colorectal Surgery: A Retrospective, Single-Center Cohort Study

Aim: The use of prophylactic antibiotics prior to colorectal surgery reduces surgical site infections. Cefazolin and metronidazole are used as a standard regimen. Ampicillin/sulbactam may be an alternative, but current data are limited. We compared the efficacy of ampicillin/sulbactam with cefazolin and metronidazole as prophylactic antibiotics. Methods: Patients who underwent colorectal surgery at Inha University Hospital between 2010 and 2020 were treated prophylactically with cefazolin and metronidazole or ampicillin/sulbactam, and observed for 30 days following surgery. The primary outcome was surgical site infections. The secondary outcomes were deep/organ infections and the need for drainage. Results: SSIs occurred in 2.6% (17/646) of the ampicillin/sulbactam group, whose rate was not inferior to the occurrence in the group receiving cefazolin and metronidazole (3.8%, 21/556). There was no significant difference between the two groups in the secondary outcomes. Conclusions: Compared to the cefazolin and metronidazole combination, ampicillin/sulbactam is not inferior as a preoperative prophylactic antibiotic regimen for colorectal surgery.