title: Long-term monitoring drug resistance by ultra-deep pyrosequencing in a chronic hepatitis B virus (HBV)-infected patient exposed to several unsuccessful therapy schemes.
abstract: The aim of this study was to analyze the spectrum and dynamics of low-prevalent HBV mutations in the reverse transcriptase (rt) and S antigen by ultra-deep pyrosequencing (UDPS). Samples were obtained from a chronically infected patient who was followed throughout a thirteen-year period. This technology enabled simultaneous analysis of 4084 clonally amplified fragments from the patient allowing detecting low prevalent (<1%) mutations during the follow-up. At baseline, HBV sequences were predominately wild-type. Under sequential HBV monotherapies including lamivudine, adefovir and entecavir, a high frequency of rtM204I mutation was detected initially as unique and then coexisting with rtM204V. Both mutations were statistically associated with rtA200V and rtV207I, respectively. Once the entecavir and tenofovir combined therapy was started, polymerase and consequently envelope gene mutations appeared at several positions at a higher frequency than before, including the entecavir resistance-associated mutation rtT184L.
authors.affiliation: Centro Nacional de Referencia para el SIDA, Departamento de Microbiología, Universidad de Buenos Aires, Argentina.
authors.forename: M
authors.initials: M
authors.lastname: Sede
authors.forename: D
authors.initials: D
authors.lastname: Ojeda
authors.forename: L
authors.initials: L
authors.lastname: Cassino
authors.forename: G
authors.initials: G
authors.lastname: Westergaard
authors.forename: M
authors.initials: M
authors.lastname: Vazquez
authors.forename: S
authors.initials: S
authors.lastname: Benetti
authors.forename: F
authors.initials: F
authors.lastname: Fay
authors.forename: H
authors.initials: H
authors.lastname: Tanno
authors.forename: J
authors.initials: J
authors.lastname: Quarleri
mesh_terms: D000998:Antiviral Agents / Q000008:administration & dosage* / Q000494:pharmacology; D058448:Biota; D004279:DNA, Viral / Q000737:chemistry* / Q000235:genetics; D024882:Drug Resistance, Viral; D019143:Evolution, Molecular; D005260:Female; D006515:Hepatitis B virus / Q000187:drug effects* / Q000235:genetics / Q000302:isolation & purification; D019694:Hepatitis B, Chronic / Q000188:drug therapy* / Q000821:virology*; D006801:Humans; D008137:Longitudinal Studies; D008875:Middle Aged; D020125:Mutation, Missense; D017422:Sequence Analysis, DNA; D017211:Treatment Failure
chemical_list: D000998:Antiviral Agents; D004279:DNA, Viral