title: Analysis of hepatitis B genotype changes in chronic hepatitis B infection: Influence of antiviral therapy.
abstract: OBJECTIVE
  The frequency of mixed hepatitis B virus (HBV) genotypes in chronic HBV (CHB) and genotype changes during natural disease evolution and as a result of antiviral therapy were investigated.
  
  
  METHODS
  Serum samples from 103 CHB patients were included in a cross-sectional study. Longitudinal study of HBV genotypes was performed in 22 patients, 17 of them under antiviral therapy (lamivudine and/or adefovir). HBV genotyping was done by the INNO-LiPA HBV assay.
  
  
  RESULTS
  Genotypes observed in the cross-sectional study: A 32% of cases, D 42%, C 2%, F 2%, and mixed genotypes 22% (mainly A/D, followed by A/G). Genotype G was found in 7% of patients, always combined with other genotypes. In the longitudinal study, genotype changes were observed only in treated patients (9 cases). Genotype A strains were positively selected in 6 of them, mainly as mixed A/D. In 6 patients, selection coincided with a decrease in HBV-DNA levels.
  
  
  CONCLUSIONS
  A high frequency of mixed HBV genotypes was observed in our setting. Selection of genotype A strains during treatment is likely an indication that sensitivity to therapy differs between genotypes A and D. The absence of changes in untreated patients suggests that HBV genotype is stable without external factors.
authors.affiliation: Department of Biochemistry, Hospital General Universitario Vall d'Hebrón, Paseo Valle Hebrón s/n, Servicio de Bioquimica, Barcelona 08035, Spain. rjardi@vhebron.net
authors.forename: Rosendo
authors.initials: R
authors.lastname: Jardi
authors.forename: Francisco
authors.initials: F
authors.lastname: Rodriguez-Frias
authors.forename: Melanie
authors.initials: M
authors.lastname: Schaper
authors.forename: Elena
authors.initials: E
authors.lastname: Giggi
authors.forename: David
authors.initials: D
authors.lastname: Tabernero
authors.forename: Maria
authors.initials: M
authors.lastname: Homs
authors.forename: Rafael
authors.initials: R
authors.lastname: Esteban
authors.forename: Maria
authors.initials: M
authors.lastname: Buti
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000998:Antiviral Agents / Q000627:therapeutic use*; D001483:Base Sequence; D002648:Child; D003430:Cross-Sectional Studies; D017931:DNA Primers / Q000235:genetics; D004279:DNA, Viral / Q000097:blood; D024882:Drug Resistance, Viral / Q000235:genetics; D005260:Female; D005838:Genotype; D006515:Hepatitis B virus / Q000145:classification / Q000187:drug effects* / Q000235:genetics* / Q000302:isolation & purification; D019694:Hepatitis B, Chronic / Q000188:drug therapy* / Q000821:virology*; D006801:Humans; D008137:Longitudinal Studies; D008297:Male; D008875:Middle Aged; D012189:Retrospective Studies; D055815:Young Adult
chemical_list: D000998:Antiviral Agents; D017931:DNA Primers; D004279:DNA, Viral