title: [Mutation patterns in the RT region of hepatitis B virus P gene in patients treated with nucleoside/nucleotide analogs].
abstract: OBJECTIVE
  To analyze mutation patterns in the RT region of hepatitis B virus (HBV) P gene in patients treated with nucleoside or nucleotide analogs.
  
  
  METHODS
  Viral DNA was extracted from 227 serum samples of chronic hepatitis B patients from September, 2005 to March, 2007. The RT region of HBV P gene was PCR-amplified and sequenced.
  
  
  RESULTS
  Known resistant mutations were found in 111 cases (48.9%) among 227 samples, 75 cases with clear therapy history. Novel mutations, including A222T, L229V and S256C, were also found. The incidence of multi-drug resistance in patients sequentially treated with lamivudine and adefovir was 25% (4/16), and none of the patients treated with lamivudine plus adefovir in combination shown multi-drug resistance.
  
  
  CONCLUSIONS
  The patterns of mutation is complex in nucleotide analogue treated patients. Switching to adefovir in lamivudine resistant patients may lead to multi-drug resistance. Novel mutations identified in this study need further investigation.
authors.affiliation: Ruijin Hospital, Shanghai Jiaotong University School of Medicine, Shanghai 200025, China.
authors.forename: Jun
authors.initials: J
authors.lastname: DENG
authors.forename: Dong-hua
authors.initials: DH
authors.lastname: ZHANG
authors.forename: De-min
authors.initials: DM
authors.lastname: YU
authors.forename: Li
authors.initials: L
authors.lastname: CHEN
authors.forename: Xin-xin
authors.initials: XX
authors.lastname: ZHANG
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000998:Antiviral Agents / Q000494:pharmacology / Q000627:therapeutic use; D004252:DNA Mutational Analysis; D004279:DNA, Viral / Q000235:genetics; D024882:Drug Resistance, Viral; D005260:Female; D015684:Gene Products, pol / Q000235:genetics*; D005814:Genes, Viral; D014644:Genetic Variation; D006515:Hepatitis B virus / Q000187:drug effects / Q000235:genetics*; D019694:Hepatitis B, Chronic / Q000188:drug therapy* / Q000235:genetics / Q000821:virology; D006801:Humans; D008297:Male; D008875:Middle Aged; D018894:Reverse Transcriptase Inhibitors / Q000494:pharmacology / Q000627:therapeutic use*; D020133:Reverse Transcriptase Polymerase Chain Reaction / Q000379:methods; D055815:Young Adult
chemical_list: D000998:Antiviral Agents; D004279:DNA, Viral; D015684:Gene Products, pol; C066027:P protein, Hepatitis B virus; D018894:Reverse Transcriptase Inhibitors