Objective: To investigate drug-resistant mutations in and genotypes of hepatitis B virus (HBV) in chronic HBV carriers using PCR sequencing technology.
Methods: Chronic HBV carriers were recruited from Tianjin Second People's Hospital between June 2013 and May 2014 and 317 were enrolled in the study according to receipt of nucleos(t)ide analogues (NAs) for at least three months prior. Drug-resistant mutations were detected by PCR followed by sequencing. SPSS21.0 was used for statistical analysis.
Results: Drug-resistant mutations were detected in 119 of the 317 patients, including 20 of 46 patients who received lamivudine (LAM), 16 of 34 patients who received adefovir (ADV), 13 of 80 patients who received entecavir (ETV), 5 of 23 patients who received telbivudine (LdT), and 65 of 124 patients who received various sequential/combined NA therapies. Each of the NAs had dominant drug-resistant mutational profiles, with rtM204I+rtL180M±rtL80I (30.9%) for LAM, rtA181T/N (21.3%), rtS213T/N (21.3%) and rtV214A (21.3%) for ADV, rtl180M (48%) for ETV, rtM204I for LdT, and rtA194T for tenofovir disoproxil fumarate (TDF). A total of 308 HBV genotypes were detected, including type B in 27 cases (8.8%), type C in 279 cases (90.6%), and type D in 2 cases (0.6%). The different HBV genotypes had no statistically significant difference in drug-resistance mutations, though (χ(2) = 1.11, P > 0.05). Two TDF drug-resistant mutations rtA194T were detected.
Conclusion: The results provide new information on NA drug-resistant mutations and HBV genotype profiles in chronic HBV carriers and may have important clinical implication for HBV drug resistance management. In addition, the data confirmed the preexisting TDF mutation rtA194T.