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.
Fosfomycin/metronidazole compared with doxycycline/metronidazole for the prophylaxis of infection after elective colorectal surgery. A randomised double-blind multicentre trial in 517 patients.
To find out if fosfomycin together with metronidazole was any better than doxycycline with metronidazole for the prophylaxis of infection before elective colorectal operations.
                Multicentre, double blind, random control trial.
                Nine Swedish hospitals. SUBJECTS-559 patients admitted for elective colorectal operations.
                Fosfomycin 8 g and metronidazole 1 g before operation and fosfomycin 8 g eight hours afterwards, or doxycycline 400 mg and metronidazole 1 g before operation, and placebo eight hours afterwards.
                Incidence of all types of infection, mortality, and side effects.
                There were no significant differences between the groups for any of the outcome measures studied, the overall abdominal infection rates (wound, deep, and septicaemia) being 4.6% and 7.4%, and the remote infection rates (pneumonia, urinary tract, and central venous line) 15.1% and 12.8%, respectively. Of the predictors studied, only duration of operation was significantly related to risk of infection.
                The combination of fosfomycin and metronidazole was as safe and effective as that of doxycycline and metronidazole in preventing infections after elective colorectal operations.