Preoperative oral antibiotic bowel preparation in elective resectional colorectal surgery reduces rates of surgical site infections: a single-centre experience with a cost-effectiveness analysis

Introduction Surgical site infections cause considerable postoperative morbidity and mortality. The aim of this study was to determine the effect on surgical site infection rates following introduction of a departmental oral antibiotic bowel preparation protocol. Methods A prospective single-centre study was performed for elective colorectal resections between May 2016-April 2018; with a control group with mechanical bowel preparation and treatment group with oral antibiotic bowel preparation (neomycin and metronidazole) and mechanical bowel preparation. The primary outcome of surgical site infection and secondary outcomes of anastomotic leak, length of stay and mortality rate were analysed using Fisher’s exact test and independent samples t-tests. A cost-effectiveness analysis was also performed. Results A total of 311 patients were included; 156 in the mechanical bowel preparation group and 155 in the mechanical bowel preparation plus oral antibiotic bowel preparation group. The study included 180 (57.9%) men and 131 (42.1%) women with a mean age of 68 years. There was a significant reduction in surgical site infection rates (mechanical bowel preparation 16.0% vs mechanical bowel preparation plus oral antibiotic bowel preparation 4.5%; P = 0.001) and mean length of stay (mechanical bowel preparation 10.2 days vs mechanical bowel preparation plus oral antibiotic bowel preparation 8.2 days; P = 0.012). There was also a reduction in anastomotic leak and mortality rates. Subgroup analyses demonstrated significantly reduced surgical site infection rates in laparoscopic resections (P = 0.008). There was an estimated cost saving of £239.13 per patient and £37,065 for our institution over a one-year period. Conclusion Oral antibiotic bowel preparation is a feasible and cost-effective intervention shown to significantly reduce the rates of surgical site infection and length of stay in elective colorectal surgery.