OBJECTIVETo develop a rapid and specific method for hepatitis C virus ( HCV) genotyping using reverse dot blot hybridization technique and investigate the distribution of HCV genotypes and subtypes in Guangdong.

METHODSThe primers and the probes targeting the 5'untranslated region (5'UTR) and core region of HCV genotypes 1b, 2a, 3a, 3b and 6a were designed, and the RT-PCR reverse dot blot hybridization (PCR-RDH) method for HCV genotyping was established. A total of 115 patients with hepatitis C were genotyped using this method, and 38 of them were also genotyped by sequencing and phylogenetic analysis to evaluate the accuracy and specificity of the method.

RESULTSOf the 115 patients, 111 were successfully genotyped to be 1b, 2a, 3a, 3b, 6a and mix-infection of 1b/2a at frequencies of 56.8%, 8.1 %, 3.6%, 5.4%, 25.2% and 0.9% respectively, and all the 15 healthy control samples showed negative results. The accuracy and reliability of the genotyping method of PCR-RDH was confirmed in 38 cases by amplification of HCV core and NS5B regions followed by DNA sequencing and phylogenetic analysis.

CONCLUSIONThis method for HCV genotyping, with high reliability and specificity, is suitable for clinical and epidemiological investigations. The prevalence of HCV genotypes 1b and 2a decreases while 1b remains the dominant genotype in Guangdong, where the prevalence of 6a significantly increases as compared with that 10 years ago.