Characterization of hepatitis virus B isolated from a multi-drug refractory patient

• Published in: Virus research 2011, Vol.155 (1), p.254-258
• Main Authors: Wei, Chen, Yu-tian, Chong, Ji-zhi, Wen, Yong-wei, Li, Gang, Li
• Format: Article
• Language: English
• Subjects: Adult; antigens; Antiviral Agents - pharmacology; Antiviral Agents - therapeutic use; chronic hepatitis B; clones; Cloning, Molecular; Cluster Analysis; cross resistance; DNA Mutational Analysis; DNA, Viral - chemistry; DNA, Viral - genetics; Drug resistance; Drug Resistance, Viral; drug therapy; genes; Genome; Genome, Viral; Genotype; Hepatitis B virus; Hepatitis B virus - genetics; Hepatitis B virus - isolation & purification; Hepatitis B, Chronic - drug therapy; Hepatitis B, Chronic - virology; Humans; Male; molecular cloning; multiple drug resistance; Mutation; Mutation, Missense; nucleosides; patients; Phylogeny; polymerase chain reaction; promoter regions; RNA-directed DNA polymerase; Sequence Analysis, DNA; Sequence Homology; stop codon; Viral Proteins - genetics; viruses
• ISSN: 0168-1702; 1872-7492
• DOI: 10.1016/j.virusres.2010.10.018

Prolonged treatment of chronic hepatitis B (CHB) with nucleoside analogues (NAs) almost invariably engenders viral resistance, and sequential NAs monotherapy can promote multi-drug resistance. This study aimed to investigate the molecular characteristics and the mutation profile of multi-drug resistant hepatitis B virus (HBV). The complete genome of HBV isolated from a multi-drug refractory patient was amplified and cloned, and 22 clones were selected for sequencing. The homology of the full-length genome between clones ranged from 98.7% to 99.9%. A precore stop codon mutation of G1896A and basic core promoter (BCP) mutations A1762T/G1764A were detected in a majority of clones. A phylogenetic analysis showed that all clones were classified as subgenotype B2. Three mutations in the surface (S) antigen region, sC76Y, sP120T and sI195M, were detected in 100%, 100% and 77.3% of the clones, respectively. In the core (C) antigen region, a mutation at codon 135 (cP135Q) was detected in 100% of clones. Lamivudine (LAM)-resistant mutations, rtL180M and rtM204V/I were detected in 86.4% of clones. Adefovir (ADV) or entecavir (ETV)-resistant mutations were not detected. Several novel mutations, such as rtT128N, rtA222T, rtS256G, rtL271M, rtS332R, and rtN/T337D, were present in a majority of clones. Furthermore, six pairs of mutations in the overlapping reverse transcriptase (RT) gene and S gene were detected. In conclusion, the complex HBV mutation profile detected in the multi-drug refractory patient highlights the problems associated with the ongoing selection of mutations, including further compensatory mutations as well as potential cross-resistance mutations.