Antibiotics covering aerobic and aerobic bacteria should be delivered orally and intravenously prior to colorectal surgery.  Antibiotics delivered within this framework will reduce the risk of postoperative SWI by at least 75%.  Further research is required to establish the optimal timing and duration of dosing, and frequency of longer-term adverse effects such as Clostridium difficile pseudomembranous colitis.
Impact of oral antimicrobial prophylaxis on surgical site infection and methicillin-resistant Staphylococcus aureus infection after elective colorectal surgery. Results of a prospective randomized trial.
The impact of oral antimicrobial prophylaxis on the surgical site infection and methicillin-resistant Staphylococcus aureus (MRSA) infection after elective colorectal surgery was evaluated by a prospective randomized single-blind study. The patients were randomly allocated to receive either mechanical bowel cleansing with polyethylene glycol alone (group 1) or mechanical cleansing plus oral antimicrobial prophylaxis with kanamycin and erythromycin for 2 days prior to surgery (group 2). In both groups, cefotiam was intravenously given twice a day for 3 days. A total of 143 patients (71 for group 1 and 72 for group 2) were eligible. The incidence of a surgical site infection was 23.9% in group 1 and 11.1% in group 2 (P = 0.04). The incidence of MRSA infection including at surgical and remote sites was 11.1% in group 1 and 5.6% in group 2 (P = 0.19). A multivariate logistic regression analysis showed that the risk of surgical site infection was influenced by the choice of the chemical bowel preparation (P = 0.03) and blood loss (P < 0.01), while an MRSA infection was predominantly influenced by blood loss (P < 0.01) followed by coexisting underlying diseases (P = 0.07). These results suggest that preoperative antimicrobial prophylaxis would be useful for reducing the incidence of a surgical site infection without increasing the risk of an MRSA infection following elective colorectal surgery.