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.
Ceftriaxone vs. ampicillin + metronidazole as prophylaxis against infections after clean-contaminated abdominal surgery.
In a prospective, controlled, double-blind study, 496 patients undergoing abdominal surgery were given antibiotic prophylaxis with a single dose of either ceftriaxone or ampicillin + metronidazole. No significant intergroup difference was found between the respective overall rates of infectious complications (3.2% and 4.9%). Analysis of the microbiologic findings showed incisional wound infections, mainly caused by gram-negative rods, to be more common in the ampicillin-metronidazole group, whereas deep wound infections were more frequent in the ceftriaxone group. It is concluded that ceftriaxone seems to be more efficient than ampicillin-metronidazole as prophylaxis against incisional wound infection, but should preferably be supplemented with an antianaerobic agent to prevent deep wound infections.