Ninety-eight patients with suspected nonperforated acute
appendicitis have to date been entered into a continuing, prospective, blinded randomized trial to determine the role of prophylactic
metronidazole in
postoperative wound infection. Twenty-six patients were excluded for the following reasons: diagnosis other than acute
appendicitis (16), perforation of the appendix (8), administration of other
antibiotics (1), and refusal to enter study (1). Seventy-two patients, 47 men and 25 women, with a mean age of 27.5 years (range 15 to 60 years), underwent
appendectomy and were studied. Thirty patients received 1 gm intravenous
metronidazole preoperatively and five intravenous doses of 500 mg
metronidazole postoperatively. Forty-two patients received placebo only. Cultures of the appendiceal stump grew aerobic cultures in 45 (62%) and anaerobic organisms in 29 (40%): Escherichia coli and Bacteroides fragilis, respectively. Six of the 72 patients (8.2%) developed
postoperative wound infections: four of 42 (9.5%) who received placebo and two of 30 (6.6%) who received
metronidazole (P = 0.54 by Fisher exact test). No toxicity from
metronidazole was observed. The
postoperative wound infection rate is insufficient to demonstrate the efficacy of
metronidazole for prophylaxis in nonperforated acute
appendicitis, although there appears to be a tendency of to assume its efficacy in this regard.