Changes Of Fecal Bifidobacterium Species In Adult Patients With Hepatitis B Virus Induced Chronic Liver Diseases

Objective The aim of this study was to characterize the composition of intestinal Bifidobacterium in patients with hepatitis B virus-induced chronic liver disease.Methods The fecal samples of16patients with chronic hepatitis B (CHB),16patients with hepatitis B virus-related cirrhosis (HBV cirrhosis), and15health subjects were collected respectively. After extracting total DNA from the samples, nested-PCR-based denaturing gradient gel electrophoresis (PCR-DGGE) was applied to analyze the diversity of the genus Bifidobacterium and then the most common bands in the profiles were identified by cloning. Meanwhile, genus-specific clone libraries were constructed to illustrate the evolutionary relationship and determine the phylotypes in each group. Finally, the predominantly observed species were selected for enumeration by real-time PCR.Results Though there was no significant difference in the diversity among the three groups (P=0.196), Bifidobacterium dentium seems to be specifically enhanced in patients as the PCR-DGGE profiles showed, which was further validated by clone library and real-time quantitative PCR. In contrast to the B. dentium, Bifidobacterium catenulatum/pseudocatenulatum were detected less frequently in the predominant profile and by quantitative PCR in HBV cirrhotics than in the controls, and the level of this species was also significantly different between these two groups (P=0.023). Although having no quantitative difference among the three groups, Bifidobacterium longum was less commonly detected in HBV cirrhotics than in CHB patients and Controls by quantitative PCR (P=0.011).Conclusion The composition of intestinal Bifidobacterium was deeply altered in CHB and HBV cirrhotic patients with a shift from beneficial species to opportunistic pathogens.