The Lamivudine/ Entacavir Resistance Mutations Among Treatment Naïve Chronic HBV Infected Patients Mashhad, Iran

 Despite significant progress in Hepatitis B Virus (HBV) treatment, the emergence of drug resistance mutations is a main challenging health threat. The data is lacking regarding circulation mutant strains in northeastern Iran; therefore, the present study was conducted to investigate HBV reverse transcriptase (RT) inhibitors drug resistance mutations in a group of treatment naïve patients in Mashhad, Iran.

 In this study, 25 patients were included. The genomic DNA was extracted from serum samples, and the RT gene of HBV was amplified using specific primers. The PCR products were then subjected to gel electrophoresis and were next sent for sequencing. Finally, the sequences were analyzed using the HBVseq database, mutation list analysis software supported by Stanford University (https://hivdb.stanford.edu).

The mean age of the patients was 42.7±16.5. Among the patients, 56% were men. Among 23 cases (92%), no resistance mutation was observed, while 2 cases showed mutations outside the YMDD motif of viral reverse transcriptase causing Lamivudine or Entecavir resistance. The detected mutations included: rt T184A, S202I, S202H, V180I, I169L, and V173L. All sequenced samples were identified as genotype D.

 Lamivudine/Entecavir resistant variants are circulating in a minority of treatment naïve patients, which may indicate transmission of mutated stains to these patients or may be due to prolonged replication of the virus. This finding might be considered an alarm for increasing circulating mutant variants.