Hepatitis B virus genotyping among chronic hepatitis B patients with resistance to treatment with lamivudine in the City of Ribeirão Preto, State of São Paulo

• Published in: Revista da Sociedade Brasileira de Medicina Tropical 2010-05, Vol.43 (3), p.224-228
• Main Authors: Haddad, Rodrigo, Martinelli, Ana de Lourdes Candolo, Uyemura, Sérgio Akira, Yokosawa, Jonny
• Format: Article
• Language: English
• Subjects: Antiviral Agents - therapeutic use; Base Sequence; Deoxyribonucleic acid; DNA; DNA, Viral - genetics; Drug Resistance, Viral - genetics; Genotype; Hepatitis; Hepatitis B; Hepatitis B virus - drug effects; Hepatitis B virus - genetics; Hepatitis B, Chronic - drug therapy; Hepatitis B, Chronic - virology; Humans; Lamivudine - therapeutic use; Molecular Sequence Data; Mutation; Mutation - genetics; Phylogeny; TROPICAL MEDICINE
• ISSN: 0037-8682; 1678-9849; 1678-9849; 0037-8682
• DOI: 10.1590/S0037-86822010000300002

Lamivudine is a nucleoside analogue that is used clinically for treating chronic hepatitis B infection. However, the main problem with prolonged use of lamivudine is the development of viral resistance to the treatment. Mutations in the YMDD motif of the hepatitis B virus DNA polymerase gene have been associated with resistance to drug therapy. So far, there have not been many studies in Brazil reporting on genotype-dependent development of resistance to lamivudine. Thus, the aim of the present study was to determine the possible correlation between a certain genotype and increased development of resistance to lamivudine among chronic hepatitis B patients. HBV DNA in samples from 50 patients under lamivudine treatment was amplified by means of conventional PCR. Samples were collected at Hospital das Clínicas, FMRP-USP. The products were then sequenced and phylogenetic analysis was performed. Phylogenetic analysis revealed that 29 (58%) patients were infected with genotype D, 20 (40%) with genotype A and one (2%) with genotype F. Mutations in the YMDD motif occurred in 20% of the patients with genotype A and 27.6% of the patients with genotype D. Despite the small number of samples, our results indicated that mutations in the YMDD motif were 1.38 times more frequent in genotype D than in genotype A.