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.
Tinidazole and doxycycline as antimicrobials in elective colorectal surgery. A randomized multicentre trial.
A prospective randomized study on the effect of doxycycline alone, tinidazole alone and the two antimicrobials in two different combinations as prophylactic antimicrobials on elective colorectal surgery is presented (Table II). The number of patients included in the study was 265. Of the four different treatment groups, the one which consisted of a single preoperative dose of tinidazole 2 g and doxycycline 200 mg, seemed to give the most favourable result. In this treatment group (n = 70), wound sepsis was recorded in 7.2% and perineal sepsis in 34.8% of the cases. Only one serious, but non-fatal intra-abdominal complication (1.4%) was observed in this group. The trial did not include a placebo group.