A bacteriological assessment of ampicillin with sulbactam as antibiotic prophylaxis in patients undergoing biliary tract operations. The West of Scotland Surgical Infection Study Group.

A prospective audit of 644 patients undergoing biliary tract operations has been conducted in ten district general hospitals. All patients received a single dose of ampicillin 2 g and sulbactam 1 g as antibiotic prophylaxis. Bacteria were cultured from the bile of 121 patients. In patients with sterile bile the incidence of postoperative infection was 2.5%, while in those with colonized bile it was 22% (P less than 0.0001). The 35 patients from whose bile bacteria of two or more species were isolated, had a higher incidence of wound infection (34%) than those whose bile yielded only one species of bacterium (17%; P less than 0.05). Seventeen of the 27 patients with colonized bile who developed postoperative infection were shown to be infected by the same organisms that had been isolated from their bile. The patients whose bile yielded organisms resistant to the prophylactic antibiotic combination did not have a significantly higher rate of infection than those from whose bile only sensitive organisms were obtained. A marked difference in sensitivity patterns between the participating hospitals was observed.