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.
Postoperative infections in colonic surgery after enteral bacitracin-neomycin-clindamycin or parenteral mezlocillin-oxacillin prophylaxis.
In a prospective randomized, blind trial, three groups of patients undergoing elective colonic surgery were compared for frequency of surgical wound infection, intra-operative wound contamination and other postoperative infections. All patients allotted to the three groups received whole gut irrigation (101 balanced salt solution) by gastric tube on the evening before surgery and were treated as follows. Group A: no antibiotics; Group B: neomycin (1 g/l) + bacitracin (50,000 IU/l) + clindamycin (900 mg/l), contained in the last 31 of irrigation fluid; Group C: mezlocillin (4 g) + oxacillin (2 g) intravenously (iv) at induction of anaesthesia, followed by two identical doses at 8 and 16 h. The rate of postoperative wound infection was highest in A (38 per cent) and much lower in B (3.3 per cent, P less than 0.002) and C (6.9 per cent, P less than 0.004). The difference between B and C was statistically not significant. In A a correlation was established between the degree of wound contamination and the occurrence of wound infection. Intra-operative wound contamination was lowest in B (30 per cent), equal in A (58.1 per cent) and B (55.2 per cent). Other infections were least frequent in group C (four of 29 patients), but were not significantly different to groups B (six of 30) and A (nine of 31). It is concluded that antibiotics together with an effective mechanical preparation considerably reduce the rate of wound infection in colonic surgery.