Objective: Hepatitis B virus (HBV) infection is a global health problem and major cause of morbidity and mortality worldwide. Chronic HBV infection leads to cirrhosis, liver failure and hepatocellular carcinoma. Increased resistance to antivirals that are used to treat chronic hepatitis B is observed over the years. In this study, we aimed to determine the frequency of lamivudine (LAM) resistance seen in chronic hepatitis B patients and the mutant profiles using multiplex PCR and reverse hybridization methods.

Material and Methods: This prospective, descriptive study was conducted between May 2007 and January 2012. A total of 50 subjects that were followed-up for chronic hepatitis B and receiving LAM therapy for at least one year at the Adnan Menderes University Faculty of Medicine, Department of Internal Medicine, Outpatient Clinics of Gastroenterology Unit were included in this study. Markers of HBsAg/anti-HBs, hepatitis B e antigen (HBeAg)/anti- HBe, and anti-HBc were studied using the Architect instrument Assay. The isolation of nucleic acid from serum samples was performed using a commercial kit (Roche Diagnostic, Germany) according to the manufacturer's instructions. HBV-DNA levels were determined using a commercial real-time polymerase chain reaction method (COBAS AmpliPrep/COBAS TaqMan, Roche, USA). Mutations of LAM resistance was determined by multiplex PCR and reverse hibridization method.

Results: Primary and compensatory mutants were detected in 12 patients (24%) who had been using lamivudine for one year. Six of 12 (50%) patients were found to be resistant to LAM (rtM204I, YIDD motif) or LAM and ADV (n=4; 33.3%). In 2 (16.7%). patients, resistance to LAM+ADV together with compensatory mutations were detected.

Conclusion: The most commonly detected mutations are rtM204I and rtL180 mutations. Lamivudine resistance in chronic hepatitis B patients in our locality of Aydın province is similar to the results of other studies in our country.