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.
Single dose mezlocillin versus three dose cefuroxime plus metronidazole for the prophylaxis of wound infection after large bowel surgery.
A prospective, randomized, controlled trial was conducted in 116 consecutive patients undergoing colorectal surgery to compare single dose prophylaxis with mezlocillin to cefuroxime plus metronidazole in three doses. Patients were randomized to receive either a single dose of iv mezlocillin (5.0 g) or three doses of iv cefuroxime plus metronidazole at 8-hourly intervals. The first dose was given on the operating table. The overall wound infection rate in the mezlocillin treated patients (n = 54) was 30% and in the patients treated with cefuroxime plus metronidazole (n = 56) 25%. This difference is not statistically significant. When trivial wound infections were disregarded the wound infection rates were 11% and 16% respectively, which again was not statistically significant.