Abstract
Japan and Thailand have high incidences of bile duct carcinoma and gallstones. The presence of Helicobacter bilis (H. bilis) detected by polymerase chain reaction (PCR) and 16S rRNA analysis in bile samples from Chileans with chronic cholecystitis was reported. The association between H. bilis in bile and biliary tract malignancies has not been investigated, and therefore the aim of this study is to determine whether malignant diseases of the biliary tract are associated with the presence of H. bilis in bile samples obtained from two high-risk populations. Bile samples from 45 Japanese and 40 Thai patients were subjected to PCR analysis using H. bilis-specific primers, and six of the H. bilis amplicons were sequenced. Thirteen out of 15 (87%) Japanese and 11 out of 14 (79%) Thai patients with bile duct or gallbladder cancer tested positive for the presence of H. bilis in their bile. Eight out of 16 (50%) Japanese and 10 out of 26 (38%) Thai patients with gallstone and / or cholecystitis tested positive for H. bilis. Only 4 out of 14 (29%) subjects without biliary disease tested positive for H. bilis among the Japanese. Bile duct and gallbladder cancer showed significantly higher positive rates for H. bilis than did the non-biliary diseases among the Japanese (P < 0.01) and the odds ratios for bile duct or gallbladder cancer with H. bilis in comparison with gallstone and / or cholecystitis were 6.50 (95%CI 1.09 - 38.63) in the Japanese and 5.86 (1.31 - 26.33) in the Thai patients. In conclusion, H. bilis infection in bile was associated with biliary tract and gallbladder cancers in two high risk populations, Japanese and Thai.