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.
Combined tinidazole and doxycycline prophylaxis in colorectal surgery. An interhospital trial.
There were no significant differences between randomized groups on either preoperative tinidazole or placebo added to pre-, per, and postoperative doxycycline. Cases of anaerobic infection among the placebos patients as well as a general trend of the parameters studied suggest that tinidazole gives added protection, i.e. that antibiotic prophylaxis should also comprise anaerobic microbes.