Antiviral Resistance Mutations and Genotype-Associated Amino Acid Substitutions in Treatment-Naïve Hepatitis B Virus-Infected Individuals from the Indian Subcontinent

Background/Aims: Antiviral resistance is a major challenge to the treatment currently available for hepatitis B virus (HBV). In this study, mutations that may affect the antiviral efficacy in treatment-naïve HBV-infected individuals were analyzed. Methods: Ninety-seven treatment-naïve HBV-infected individuals were included in this study. HBV reverse transcriptase (rt) domains were sequenced and nucleotide differences were compared to GenBank wild-type sequences. Furthermore, HBV genotypes, subgenotypes and subtypes were determined by analyzing surface gene sequences. Results: An adefovir-related rtI233V mutation was identified in 4 subjects. The rtS213T lamivudine and entecavir refractory mutant was presented in 3 individuals. Altogether, drug-related, atypical and novel HBVrt amino acid substitutions were seen in 73 positions. The HBV genotypes A, C, D and G were depicted in 15, 21, 60 and 1 individuals, respectively. There were 17 HBVrt amino acid substitutions that are associated with certain genotypes of HBV. Mutations in HBVrt corresponded to established surface gene mutations in 9 patients. Conclusion: This data shows that antiviral-resistant HBV strains do exist in treatment-naïve individuals in Received: May 27, 2010 Accepted after revision: November 30, 2010 Published online: February 11, 2011 Prof. Priya Abraham, MD, PhD Department of Clinical Virology, Christian Medical College Vellore 632 004 (India) Tel. +91 416 228 2312, Fax +91 416 223 2035 E-Mail priyaabraham @ cmcvellore.ac.in © 2011 S. Karger AG, Basel 0300–5526/12/0551–0036$38.00/0 Accessible online at: www.karger.com/int D ow nl oa de d by : 54 .7 0. 40 .1 1 11 /2 3/ 20 17 2 :1 5: 08 P M