Antibiotics, biliary sepsis, and bile duct stones

Bacteriologic studies of bile and blood cultures of 579 patients with ductal stones and infected bile revealed that 121 patients (21%) had associated bacteremia. Analysis of bile and stone cultures showed that Escherichia coli, Klebsiella sp, Enterobacter sp, Enterococcus sp, and Streptococcus sp were the most commonly isolated bacteria. Two-thirds of the patients with bacteremia had similar organisms isolated from blood and bile. Pharmacokinetic studies of the hepatic/biliary excretion profiles of ceftazidime, cefoperazone, imipenem, netilmicin, and ciprofloxacin were performed by ERCP and nasobiliary catheter drainage. The bile samples obtained immediately after cannulation from patients with complete biliary obstruction contained low or undetectable levels of the antibiotics administered--the exception being ciprofloxacin, which was present at a concentration of 20% of the serum level. In vitro determination of minimum inhibitory concentration of the aforementioned antibiotics against 199 isolates of biliary pathogens revealed imipenem and ciprofloxacin to have the highest antimicrobial activity. Based on pharmacokinetic studies and in vitro susceptibility findings, we conclude that ciprofloxacin is superior to the other tested antibiotics in prophylaxis and treatment of biliary sepsis.