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.
Topical ampicillin in addition to a systemic antibiotic prophylaxis in elective colorectal surgery. A prospective randomized study.
Prophylactic use of topical ampicillin in addition to intravenous ampicillin and metronidazole was studied in a randomized trial including 203 consecutive patients undergoing elective colorectal surgery. All received ampicillin, 1 g X 3, and metronidazole, 0.5 g X 3, intravenously for at least three days from induction of anesthesia, and 105 also received topical ampicillin, 1 g, in each of the surgical wounds. Deep wound infection or dehiscence was seen in 12 of 105 having both administrations of antibiotics, and in nine of 98 having only intravenous antibiotics. The two groups were similar according to distribution of sex, age, type of surgery, and efficiency of bowel preparation. Topical ampicillin should be omitted in elective colorectal surgery when systemic prophylaxis with ampicillin and metronidazole is used.