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.
A comparison of single-dose systemic Timentin with mezlocillin for prophylaxis of wound infection in elective colorectal surgery. University of Melbourne Colorectal Group.
A prospective, randomized, single-blind, controlled clinical trial was undertaken to compare two different prophylactic antibiotic single-dose regimens in patients undergoing elective colorectal surgery. Timentin, a combination of ticarcillin and clavulanic acid, was administered intravenously (3.1 g) to 87 patients. Mezlocillin, a semisynthetic penicillin was given intravenously (2.0 g) to 98 patients. The wound infection rate was 10.6 percent in patients receiving Timentin and 9.7 percent in those receiving mezlocillin (P greater than .05). Multivariate analysis of factors possibly affecting the wound infection rate showed that the presence of a colostomy preoperatively, fecal contamination at surgery, and the surgical group were the only factors that independently achieved a statistically significant association with the development of a postoperative wound infection in this trial (P less than .0001).