Bacteriology of hepatolithiasis

Abstract

Hepatolithiasis is associated with bile stasis and bacterial infection. Gallstones found in the intrahepatic bile duct are mostly calcium bilirubinate stones, the presence of which is closely related to the presence of bacteria. In the present study, a high incidence of bile infection was found in hepatolithiasis: 52 of 54 cases (96.3%). This is in concordance with the other reports from Japan as well as from East Asia. E coli was the most frequent isolate followed by Klebsiella, Streptococcus (D), and Pseudomonas. Because of the frequent isolation of E coli in calcium bilirubinate stone cases, beta-glucuronidase from E coli has been thought to be responsible for the formation of calcium bilirubinate stones by effecting hydrolysis of bilirubin glucuronide to free bilirubin, which is insoluble in water. The recent introduction of improved anaerobic culture techniques has led to an increasing number of reports on the presence of anaerobes in the biliary tract. Anaerobes were isolated in 6 of 29 cases of hepatolithiasis (20.7%) in our series but more frequently in Kaohsiung, Taiwan (25 of 57 cases, or 44.4%). Bacteroides and Clostridium were the most frequent isolates from the biliary tract and were shown to have beta-glucuronidase activity. Anaerobes were often found together with aerobes, suggesting the possibility of a synergistic effect that may influence the occurrence and development of cholangitis, which is often associated with hepatolithiasis. Though the biliary tract and liver are usually sterile, when an infection of the biliary tract occurs the route by which bacteria reach the region is thought to be hematogenous, lymphatic, or direct intraluminal ascending infection, the last being the most likely. Treatment of cholangitis associated with hepatolithiasis should be directed toward the removal of stones and termination of bile stasis. When cholangitis ensues, control of bacterial infection by antibiotics should be started without delay. The choice of antibiotics in controlling cholangitis is presented.