Hepatitis C virus genotype and subtype distribution in Chinese chronic hepatitis C patients: nationwide spread of HCV genotypes 3 and 6

BACKGROUND: Hepatitis C virus (HCV) genotype and subtype are related to disease progression and response to antiviral therapy. Current HCV genotype and subtype distribution data, especially for genotypes 3 and 6, are limited in China. Our purpose was to investigate the current HCV genotype and subtype distributions in chronic hepatitis C patients in China. METHODS: Chronic hepatitis C patients (n = 1012) were enrolled, and demographic information and possible transmission risk factors were collected. Serum samples were subjected to reverse-transcription polymerase chain reaction, followed by direct DNA sequencing and phylogenetic analysis of the NS5B and core/E1 regions to determine HCV genotypes/subtypes. The geographical distributions of HCV genotypes/subtypes were analyzed. Demographic information and transmission risk factors were compared between different HCV genotypes/subtypes. RESULTS: Four genotypes and seven subtypes of HCV were detected in 970 patients. Subtypes 1b, 2a, 3a, 6a, 3b, 6n, and 1a were detected at frequencies of 71.96 %, 19.90 %, 3.20 %, 2.16 %, 1.96 %, 0.41 %, and 0.41 %, respectively. Genotypes 3 and 6 showed an increasingly wide geographic distribution over time. Patients with subtypes 1b and 2a were older than those with 3a, 3b, 6a, and 6n subtypes (p < 0.05 in all subtypes). More genotype 1 and 2 patients underwent blood transfusion than those with genotype 3 (all p < 0.05). More genotype 3 and 6 patients had a history of intravenous drug use than those with genotypes 1 and 2 (all p < 0.05). CONCLUSIONS: Though subtypes 1b and 2a are still the most prevalent HCV subtypes in China, genotype 3 and 6 HCV infections have already spread nationwide from southern and western China. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (doi:10.1186/s12985-015-0341-1) contains supplementary material, which is available to authorized users.