A multicentre study to compare piperacillin with the combination of netilmicin and metronidazole for prophylaxis in elective colorectal surgery undertaken in district general hospitals.

We have conducted a multicentre randomized study to compare piperacillin with the combination of netilmicin and metronidazole in patients undergoing elective colorectal surgery. There was no significant difference in the incidence of operation-related infection, chest or urinary tract infection. Major life-threatening sepsis occurred in 6% and the overall incidence of operation-related infection was 24%. Organisms which normally inhabit the bowel lumen were cultured from most of the postoperative infections; however, Staphylococcus aureus was isolated as a causative organism in nine patients in the piperacillin group compared with none in the netilmicin and metronidazole group. We are concerned at the high incidence of infection in both groups, and we believe that other factors in addition to prophylactic antibiotics need to be evaluated if the incidence of infection is to be reduced further.