Molecular Detection of Helicobacter Species and Other Bacteria in Human Bile Samples of Patients with Biliary Diseases

Abstract

Background & study aims: Bacterial infection is accepted as a precipitating factor in gallstone formation and recent studies have revealed the presence of Helicobacter species in the biliary system. The aim is to determine whether bacterial infections could be detected in bile obtained at ERCP and to evaluate the prevalence of these infections in patients with biliary diseases. Patients & methods: 102 consecutive patients undergoing ERCP for various indications at Tehran Taleghani Hospital were asked to participate in this study. Bile juice was aspirated after selective cannulation of the common bile duct and stored at -20°C. Each of the patient samples had been tested by PCR on 16s rRNA region and RFLP-DGGE for bacterial infections. Results: Helicobacter DNA was detected by PCR in bile samples 2 out of 74 with gallstone diseases, 1 out of 15 pancreatobiliary malignancies and 1 out of 13 other benign biliary diseases (p=0.582). Direct sequencing confirmed strains of H. pylori in all four bile samples. Bacteria were detected by the amplification of 16s rRNA 43.2% in gallstone diseases, 53.3% in pancreatobiliary malignancies and 53.8% in other benign biliary diseases (p=0.646). Conclusion: E.coli, Enterococcus, Klebsiella, Pseudomonas, Acinetobacter and H. pylori were found in the biliary system, suggesting that these bacteria are of etiological importance in gallstone formation and other biliary diseases.