Indications for antibiotic prophylaxis and treatment in patients undergoing appendicectomy

Abstract

Bacteroides species were isolated from 225 (66%) of positive appendix fossa swabs examined from 830 patients undergoing appendicectomy and were the commonest organisms isolated in pure culture. Pathogenic bacteria were more frequently isolated from the appendix fossa swab in perforated appendicitis. The incidence of wound infection in 553 patients who did not receive antibiotic treatment was 22%and this was highest in perforated appendicitis (69%)and appendix abscess (94%)and lowest where chronic appendicitis (11%)was present. Bacteroides species were isolated from 899 of wound infections where a mixed culture was present and 82%when a single organism was found. The role of antibiotic prophylaxis is important in reducing the rate of wound infection, especially in perforated appendicitis, but treatment should also be given when Bacteroides fragilis is isolated from the appendix fossa swab in view of the high incidence of wound infection in these cases. The use of clindamycin, lincomycin and metronidazole is considered more appropriate than other antibiotics because of their high level of antibacterial activity against anaerobic bacteria. It is important to detect ‘patients at risk’in view of the dangers associated with widescale use of antibiotic prophylaxis. Despite many published reports, the morbidity associated with appendicectomy is high and further controlled studies involving the close co-operation of the surgeon and microbiologist are needed.