Prevalence of hepatitis C virus (HCV) genotypes and increase of type 4 in central Italy: an update and report of a new method of HCV genotyping.

Hepatitis C virus (HCV) genotyping is very useful for identifying the patients (type 1 and 4) that need more aggressive management. In recent years, genotype 4 has shown spread in different parts of Europe. The aim of this study was to update on the prevalence of HCV genotypes of 288 patients in Central Italy, to analyze the possible increase of genotype 4 and to evaluate a new simple genotyping method. A line-probe assay (LiPA, Bayer) was used based on the reverse hybridization of HCV genome fragments previously amplified and biotinylated by a polymerase chain reaction (PCR) assay, COBAS System Amplicor HCV monitor version 2.0 (Roche) or previously amplified by COBAS Ampliprep/TaqMan HCV test (Roche). This last method uses non-biotin-labeled primers, therefore we added for each sample 10 microl of amplified HCV products, 10 microl of denaturation solution and 10 microl of biotinylated-nested primers (Bayer) to utilize the genotyping procedure previously used. The results showed that the prevalence of type 1, 2 and 3 (482, 34.6 and 10.5%, respectively) as well as the prevalent subtypes, 1b and 2a/2c (30.7 and 27.2%, respectively) were similar to previous data. Type 1 and 2 were statistically associated with an older group of patients when compared with type 3 and 4 (p < 0.001). Type 3 and 4 showed a significant prevalence of male patients compared to type 1 and in particular to type 2 (p < 0.014). The prevalence of type 4 was 5.6% in 2004, 6.1% in 2005 and 9.9% from January to July 2006. Type 4 showed an increase of male prevalence over a 3-year period (p < 0.001). In conclusion, subtype 1b and 2a/2c showed a very similar prevalence, age and gender distribution in Central Italy. The type 4 patient group was analyzed because an increase of this genotype (1.8 times) was detected.