Hepatitis B in the Northwestern region of Sao Paulo State: genotypes and resistance mutations

In Brazil, few studies on the molecular aspects of hepatitis B virus (HBV) infection have been conducted in the interior regions of Sao Paulo State. This study aimed to identify HBV genotypes and evaluate strains with resistance mutations for nucleoside analogues in the Administrative Region (AR) of the municipality of Sao Jose do Rio Preto. We performed nested PCRs of 127 samples from the Health Care Services of the AR to amplify, sequence and analyze fragments of the HBV DNA, in order to identify genotypes and resistance mutations. The HBV S/Pol regions of 126 samples were successfully amplified and sequenced. Five different genotypes were found, and the main ones were A, D and F; a greater number of samples contained the subgenotypes A1 (n = 51; 40.5%), D3 (n = 36; 28.6%), A2 (n = 14; 11.1%) and F2a (n = 9; 7.1%). Resistance mutations (rtM204V/I/S) associated or not with compensatory mutations (rtL180M, rtV173L) were identified in 13.9% (5/36) of patients undergoing viral treatment and 1.1% (1/90) of naïve patients. The diversity of genotypes/subgenotypes found is probably due to the intense migration occurring in the region. These data can complement epidemiological and clinical surveillance, and can be used for a more effective management of chronic HBV patients.