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.
Prophylactic antibiotics in elective colorectal surgery.
A randomized prospective study was conducted on 194 patients who underwent elective colorectal surgery for carcinoma. All patients received the same mechanical bowel preparation. In addition, patients in group A received oral neomycin and erythromycin base; patients in group B received systemic metronidazole and gentamicin, while patients in group C received both oral and systemic antibiotics. Postoperative septic complications related to colorectal surgery occurred in 27.4 per cent, 11.9 per cent and 12.3 per cent respectively in groups A, B and C (chi 2 = 7; P less than 0.05). The incidence of sepsis in groups B and C was almost identical. Patients who received oral antibiotics alone (group A) had significantly higher risks of postoperative sepsis when compared with patients in either group B or group C (P less than 0.05). As there is no additional advantage of combining oral and systemic antibiotics, we recommend systemic metronidazole and gentamicin to be used with mechanical bowel preparation in elective colorectal surgery.