A brief course of colon preparation with oral antibiotics

We carried out a prospective clinical trial of colon preparation with a regimen of oral antibiotics starting on the day before surgery. The patients were assigned to one of two groups consisting of either a mechanical preparation alone group (group 1, 45 cases) or a mechanical bowel preparation with oral antibiotics group (group 2, 38 cases). Group 2 received kanamycin and metronidazole three times on the day before surgery. Cefmetazole was administered for 3 consecutive days as prophylaxis in both groups. In a study using intraoperative mucosal swabs, the rates of group 2 patients with cultures yielding anaerobes or Gram-negative bacteria were significantly lower than those of group 1. There were no significant differences in the rates of patients with cultures yielding fungi or Gram-positive organisms. The positive culture rate in the peritoneal fluid of group 1 was also higher than that of group 2 (40%, 16%, P < 0.05). The surgical site infection rate was 18% in group 1 and 13% in group 2. Organisms isolated from the sites of postoperative infections were not identical with those from the peritoneal fluid. This relatively brief course preparation minimized the emergence of resistant strains. However, in spite of the colonic bacterial burden and the intraoperative inoculation in the patients with mechanical cleansing alone, their incidence of subsequent infections was comparable to that of patients who were administered oral antibiotics provided that the prophylactic antibiotic was administered for 3 days after surgery.