A prospective controlled trial of cephradine and metronidazole as prophylaxis with abdominal hysterectomy

Abstract

Postoperative infections in abdominal and pelvic wounds after abdominal hysterectomy are mostly due to more than one organism, representing the wide range of anaerobic and aerobic bacteria present in the vagina of the asymptomatic female (Kauppila et al., 1983). Anaerobes, notably the Bacteroides species, may be found alone or in association with aerobes in 90 per cent of pelvic abscesses (Seligman, 1978). Researchers have been unable to demonstrate wound infections in animal models after inoculation of pure Bacteroides cultures and some doubt has been cast on the pathogenicity of this species. Kelly (1980), in a series of elegant experiments, demonstrated a pathogenic synergy between Escherichia coli and Bacteroides fragilis. When individually subinfective doses of these organisms were inoculated together into surgical wounds, severe sepsis resulted. Similarly, when peri-operative wound swabs cultured both aerobes and anaerobes the incidence of postoperative wound infection was 71 per cent compared to 13 to 22 per cent if anaerobes or aerobes were isolated singly. Infections caused by a combination of aerobic and anaerobic organisms are dependent on the presence of both and reduction of one kind of bacteria may preclude infection by the other. If either the anaerobic or aerobic population is decreased at the time of operation, there will be reduction in the rate of postoperative sepsis.