Biliary bacteria, antibiotic use, and wound infection in surgery of the gallbladder and common bile duct.

That clinical risk groups predict postoperative infection in biliary operations has recently been challenged. To reevaluate the risk of infection, we studied 215 patients stratified by clinical risk factors. Of 100 patients having simple "low-risk" cholecystectomy, 11 had positive bile cultures (90% pure), and one with sterile bile got a staphylococcal wound infection (WI). Among 92 "high-risk" patients with acute cholecystitis, obstructive jaundice, or choledochal stones, 42 had positive bile cultures (44% pure, 12% anaerobes). One of 52 patients who received preoperative cefazolin got a staphylococcal WI, but ten of 40 patients without antibiotic therapy developed WIs, nine caused by organisms that also grew from the bile. Of 23 patients with obstructive cholangitis, 22 had positive bile cultures (88% mixed, 23% anaerobes). Despite antibiotic therapy, four developed WIs caused by these organisms. The concept of clinical risk factors is validated.