Objectives: To investigate the multiple drug resistance (MDR) profiles in patients who took sequential therapy after adefovir treatment failure. Methods: 210 patients’ clinical data and serum samples who took sequential lamivudine therapy as rescue therapy after adefovir treatment failure were collected from 5 hospitals in China during December 2007 to December 2009. PCR product population sequencing was used for screening MDR. PCR product cloning sequencing were used for further analyzing resistance profiles. Results: 3 MDR patients were identified with population sequencing. All 3 patients are genotype C patients. Population sequencing showed rtM204V + rtL180M +rtA181V mutation in all 3 patients. And 64 clones were get from 3 patients. Cloning sequencing results were showed in Chart1. All clones carried mutations resistant to lamivudine and adefovir. rtM204V + rtL180M +rtA181V is the major mutation type in 3 MDR patients (67.2%). Besides, all 3 patients carried clones with entecavir resistance mutation (rtM250V/H, rtS202I, rtI169V), though in minority (23.4%). Conclusions: Single lamivudine as rescue therapy for adefovir treatment failure may cause MDR. rtM204V + rtL180M + rtA181V is the major form of mutation in these patients. Entecavir resistance mutation maybe induced with sequential therapy.

China is a multicultural country that has arisen from its 56 ethnicities, with a diverse population of over 1.3 billion people and an imbalanced economic development. The health care system in China is tending to be overall funded through urban and rural health insurance plans. Although China has invested in the basic research of genome science, public health genomics-related programs and services in China started late. Prenatal screening is offered as part of routine clinical prenatal services and is free of charge in some economically advanced cities. Newborn screening programs are mandated throughout the country but vary between provinces and territories in terms of organization and diseases screened for; most screening tests are paid by out-of-pocket expenses. Genetic tests are encouraged while there are only one accredited state laboratory and few territorial laboratories in China. Further national genomics policies are needed in China in a range of genetic issues and infrastructure of public health genomics. Careful measurement is essential to understanding the nature and scale of the task ahead.