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.
Prophylactic antimicrobials in elective colorectal and biliary surgery.
In 97 patients undergoing elective biliary (44) or colorectal (53) surgery, cases were randomly allocated to receive peri-operative prophylaxis with either cefoxitin (Mefoxin; MSD) or metronidazole, penicillin and tobramycin (MPT). Sepsis occurred in 3 of the biliary cases (6,8%) and in 16 of the colorectal cases (30,2%). In the colorectal group sepsis occurred equally in patients receiving cefoxitin (22,2%) or MPT (38,5%) (P = 0,20). Patients who developed sepsis did not have a prolonged hospital stay; strict criteria were used to define sepsis in this study and this explains the apparently high sepsis rate. A positive wound culture at the end of the operation was more common after colorectal surgery (30,2%) than after biliary surgery (4,6%) and was associated with a higher subsequent infection rate (P = 0,02).