An improved reverse dot hybridization for simple and rapid detection of adefovir dipivoxil-resistant hepatitis B virus

Resistant mutants induced by adefovir dipivoxil in hepatitis B virus isolates

AIM: To investigate the loci of adefovir dipivoxil (ADV)-induced resistance in hepatitis B virus (HBV) isolates and optimize the management of ADV-treated patients.

METHODS: Between June 2008 and August 2010, a cross-sectional control study was conducted comprising 79 patients with chronic HBV infection-related liver disease who had been administered ADV monotherapy. Patients underwent liver imaging. Serum DNA extracts were analyzed for HBV DNA levels, genotypes, and serology markers, and deep sequencing of the HBV P gene was performed.

RESULTS: ADV-resistant patients were found either with a single mutated locus, or with coexisting mutated loci. The most prevalent mutations were rtA181T, rtV214A, and rtN236T. Twenty-six patients had more than two mutated loci. The mutants were distributed among the patients without any significant affinity for gender, age, end-stage of liver disease, complications of non-alcoholic fatty liver disease, or HBV DNA levels. Patients with the rtA181T mutant were primarily infected with genotype C and e-antigen negative HBV, while patients with the rtN236T mutant were primarily infected by genotype B HBV (χ² = 6.004, 7.159; P = 0.023, 0.007). The duration of treatment with ADV was shorter in the single mutant group compared with the multi-mutant group (t = 2.426, P = 0.018).

CONCLUSION: Drug-resistant HBV mutants are complex and diverse. Patients should receive the standard and first-line antiviral treatment, strictly comply with medication dosage, and avoid short-term withdrawal.

Use of ALLGIO probe assays for detection of HBV resistance to adefovir in patients with chronic hepatitis B, Kerman, Iran

Hepatitis B virus (HBV) infection is contagious with transmissiobn vertically or horizontally by blood products and body secretions. Over 50% of Iranian carriers contracted the infection prenatally, making this the most likely route of transmission of HBV in Iran. To evaluate the resistance to adefovir (ADV) therapy in patients with chronic hepatitis B infection, a study was conducted on 70 patients (63 males and 7 females), who had received in first line lamivudine and second line adefovir. All were tested for the presence of hepatitis B surface antigen (HBsAg), hepatitis B envelope antigen (HBeAg), serum alanine amino transferase (ALT) level and HBV DNA load before and after treatment with ADV. In all samples, resistance to lamivudine and ADV was tested with real time PCR. Among seventy patients with chronic hepatitis B infection, 18 (25.7%) were resistant to LAM and 8 (11.4%) were resistant to ADV. Only one patient was negative for the presence of HBS-Ag (5.6%) and two were negative for HBe-Ag (11.1%). In this study we used a new method (ALLGIO probe assay) that has high sensitivity in detection of adefovir resistance mutants, which we recommend to other researchers. Mutant strains of the YMDD motif of HBV polymerase can be found in some patients under treatment with lamivudine and ADV. ADV has been demonstrated to be efficient in patients with lamivudine resistant HBV.