Effect of Preoperative Oral Antibiotics for Prevention of Incisional Surgical Site Infection After Colorectal Surgery: A Propensity Score Matching Study

<i>Background and Objectives:</i> Recent findings suggest that combining mechanical bowel preparation (MBP) and preoperative oral antibiotics (OAs) decreases the risk of incisional surgical site infections (iSSIs) in colorectal surgery; however, this finding remains controversial. This study examined the efficacy of OAs and MBP in colorectal surgery using propensity score matching (PSM). <i>Materials and Methods</i>: Between January 2015 and December 2020, 559 patients with colorectal tumors underwent MBP followed by colorectal surgery. The multivariate analysis used a COX proportional hazards model to extract risk factors for iSSI. PSM was performed to balance the impact of potential co-factors of OAs with MBP (OA) and MBP alone (non-OA) on superficial SSI incidence. <i>Results</i>: The multivariate analysis identified non-OA use as an independent risk factor for iSSIs (odds ratio [OR]: 2.44, 95% confidence interval [CI]: 1.22-4.88, <i>p</i> = 0.0112). After matching the cohort, both OA and non-OA groups were divided into 217 cases each. The incisional SSI rate was significantly lower in the OA group (<i>n</i> = 338) than in the non-OA group (1.61% vs. 5.07%; OR 3.4; 95% CI; 0.123-0.707; <i>p</i> = 0.0062). <i>Conclusions</i>: This study revealed that OAs with MBP markedly reduced SSI rates. OAs with MBP should be adopted in colorectal surgery.