Prophylactic metronidazole in electrive colo-rectal surgery.

38 patients participated in a double blind study comparing the effect of a single dose of 2.0 g metronidazole given 15 hours prior to surgery with a placebo in reducing postoperative infections after elective colonic surgery. In 17 patients given metronidazole, only 2 had infections caused by aerobes, no anaerobe was recovered. Among 8 infected patients among a total of 21 in the placebo group, there were 5 anaerobic isolates (Bacteroides 3, peptococci 1, clostridia 1) and 8 aerobic bacteria. There was a significant difference between both total number of infections in the groups receiving metronidazole and placebo (p = 0.015). In addition, the clinical course of the 2 infections in the metronidazole group was moderate compared to that in the placebo group. Suppression of anaerobes appears to have enabled the body to better eliminate aerobes as well, since fewer aerobes were found in the metronidazole group. It is concluded that metronidazole given as short term prophylaxis produces suffiecent antibacterial levels in tissues and body fluids during and shortly after operation to significantly reduce the frequency of postoperative infections.