title: Detection of rtN236T mutation associated with adefovir dipivoxil resistance in Hepatitis B infected patients with YMDD mutations in Tehran.
abstract: OBJECTIVE
  The risk of adefovir dipivoxil resistance emergence has increased in lamivudine-resistant hepatitis B infected patients. The mutations known as causing adefovir resistance, rtN236T and rtA181V/T, are detected within the D and B functional domain of the HBV polymerase, respectively. In this study, we intended to determine the pre-existing adefovir-resistance mutations in patients infected with LAM resistant mutants prior to starting adefovir therapy.
  
  
  METHODS
  The study included 30 patients with chronic hepatitis B with lamivudine resistance mutations in the YMDD motif that experienced viral breakthrough.
  
  
  RESULTS
  After alignment of protein coding sequences, the rtN236T mutation was observed in two (6.6%) patients, while twenty-eight others had neither rtN236T, nor rtA181V/T mutation. All 30 patients were infected with genotype D of hepatitis B virus.
  
  
  CONCLUSIONS
  The early detection of LAM-resistance mutations may allow a timely chance of therapy to avoid hepatitis flare-up. This data suggests that monitoring of ADV-resistance mutations in ADV naïve patients can be considered in selecting the appropriate anti-viral regimen.
authors: Antimicrobial Resistance Research Center, Tehran University of Medical Sciences, Tehran, Iran.
authors: Seyed Hamidreza
authors: SH
authors: Monavari
authors: Hossein
authors: H
authors: Keyvani
authors: Hamidreza
authors: H
authors: Mollaie
authors: Rouhollah Vahabpour
authors: RV
authors: Roudsari
keywords: Hepatitis B virus; Lamivudine; adefovir dipivoxil; mutation; resistance