Background: Surgical site infection (SSI) is a critical issue in colorectal surgery because it decreases postoperative patient quality of life. The rate of SSI in patients with ulcerative colitis (UC) receiving immunosuppressive therapy is particularly high, suggesting that the SSI rate may increase with the introduction of biologic agents.

Methods: UC patients who underwent two-stage restorative proctocolectomy at our institution between April 2012 and December 2023 were included in this study. Clinical characteristics were analyzed and compared between an SSI group and a non-SSI group; possible risk factors for SSIs were also analyzed. Additionally, the following anti-SSI measures adopted at our hospital were included as explanatory variables: laparoscopic surgery, oral antibiotic prophylaxis and change of surgical instruments before wound closure.

Results: In total, 501 UC surgical patients were included. The incidence of overall SSIs was 45/501 (8.9%). The rates of incisional SSIs and organ/space SSIs were 26/501 (5.1%) and 30/501 (5.9%), respectively. Oral antibiotic prophylaxis was identified as a risk factor for overall SSIs (odds ratio: 0.45, 95% CI 0.20-0.99, p = 0.02), incisional SSIs (odds ratio: 0.34, 95% CI 0.11-1.03, p = 0.03) and organ/space SSIs (odds ratio: 0.35, 95% CI 0.12-0.98, p = 0.04). The use of biologic and immunosuppressive agents was not associated with any SSIs.

Conclusions: Nonadministration of oral antibiotic prophylaxis was identified as a risk factor for SSIs. Oral antibiotic prophylaxis before restorative proctocolectomy may improve the postoperative quality of life of UC patients by preventing SSIs.

Keywords: Oral antibiotic prophylaxis; Postoperative complications; Restorative proctocolectomy; Surgical site infection; Ulcerative colitis.

© 2025. The Author(s).