The Effect of Preoperative Oral Antibiotics in the Prevention of Surgical Site Infection after Colorectal Surgery: A Propensity Score Matching Study

Objectives Recent findings suggest that combining mechanical bowel preparation (MBP) and preoperative oral antibiotics (OAs) decreases the risk of surgical site infections (SSIs) 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). Methods Between January 2015 and December 2020, 620 patients with colorectal tumors underwent MBP followed by colorectal surgery. OAs were initiated in our hospital in July 2017. PSM was performed to compare the effects of OAs and MBP (OA) versus MBP alone (non-OA) on the rate of superficial SSI. Results A total of 338 patients received OAs. Significant differences were observed in the American Society of Anesthesiologists performance status (ASA-PS) and the presence of tumor obstruction between the OA and non-OA groups. The OA and non-OA groups were matched using PSM based on the following factors: sex, age, body mass index, tumor location, presence of obstruction by the tumor, ASA-PS score, presence of smoking, presence of diabetes mellitus, and preoperative therapies, which resulted in the exclusion of significant differences. Univariate analysis showed that laparotomy, rectum, stomata, and non-OA use were associated with SSIs (P = 0.0446, 0.0432, 0.0219, and 0.0124, respectively). A multivariate analysis of these four variables identified non-OA use as an independent risk factor for SSIs (hazard ratio: 2.44, 95% confidence interval: 1.22–4.88, P = 0.0112). Conclusions This study revealed that OA plus MBP markedly reduced SSI rates. Therefore, OA with MBP should be adopted in colorectal surgery.