Objective: To explore the characteristics of mutation in HBV polymerase (P) gene reverse transcriptase region (RT region) in lamivudine-resistant chronic hepatitis B (CHB) patients.
Methods: This study involved 115 CHB patients who developed clinical resistance to lamivudine. Direct sequencing of the PCR products was used to detect lamivudine genotypic resistance.
Results: Lamivudine resistant mutation was detected in 103 patients, and the major mutations included rtL180M+rtM204V and rtM204I, accounting for 58.3% and 22.3%, respectively. Other resistant substitutions included rtL80V/I, rtT184S, and rtA200V, and combined mutation of triple resistant substitutions was detected in HBV RT region of 5 patients by direct sequencing.
Conclusion: For lamivudine-treated patients, combined mutation at the sites other than rtL180 and rtM204 in HBV P gene should also be detected for drug resistance evaluation.