[Hepatitis C virus genotyping: comparison of the Abbott RealTime HCV Genotype II assay and NS5B sequencing].
ABSTRACT Hepatitis C virus genotyping is needed for treatment decision and monitoring. The results of a genotyping assay based on real-time PCR and TaqMan chemistry were compared with the results of NS5B region sequencing.
One hundred and two sera (genotypes 1-6) were tested. Amplification and detection of viral RNA were performed with the Abbott RealTime HCV Genotype II assay targeting 5'non-coded region (5'NC) for the identification of genotypes 1 to 6 and NS5B, for 1a and 1b subtypes detection. Sequencing of 5'NC fragment was used to resolve discrepant results.
No indeterminate results were obtained. Concordance with NS5B sequencing was 93% (95 on 102), 96% at the genotype level (98 on 102) and 93% for genotype 1 subtyping (40 on 43). Discordant genotyping results were a 2f subtype identified as 5, a 6a typed as 1, a 3a identified as a 1-3 co-infection and a 4r identified as a 1-4 co-infection. Discordant subtyping results were 2 1b subtypes only typed as 1 and a 1e identified as 1a.
Abbott RealTime HCV Genotype II assay is a rapid, automated and simple to interpret method for HCV genotyping. It allows the detection of possible mixed infections which might have a negative impact on therapeutic response. However, the discrepant results found in this small series underline the need for assay optimization.
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ABSTRACT: BACKGROUND: Hepatitis C virus (HCV) genotyping is mandatory for tailoring dose and duration of pegylated interferon-α plus ribavirin treatment and for deciding on triple therapy eligibility. Additionally, subtyping may play a role in helping to select future treatment regimens that include directly-acting antivirals. However, commercial assays for HCV genotyping fail to identify the genotype/subtype in some cases. OBJECTIVE: Our aims were (i) to determine the success rate of the commercial genotyping assay Abbott RealTime HCV Genotype II at identifying the genotype and the HCV-1 subtype; and (ii) to phylogenetically characterise the obtained indeterminate results. STUDY DESIGN: HCV genotyping results obtained between 2009 and 2012 in a Spanish reference hospital were reviewed. A total of 896 people were genotyped with the Abbott RealTime HCV Genotype II assay. Specimens with an indeterminate result were retrospectively genotyped using the reference method based on the phylogenetic analysis of HCV NS5B sequences. RESULTS: Using the commercially available assay, an indeterminate HCV genotype result was obtained in 20 of 896 patients (2.2%); these corresponded to genotypes 3a, 3k and 4d. Importantly, 8.6% of all cases where genotype 3 was detected were indeterminate. In addition, the HCV-1 subtype was not assigned in 29 of 533 cases (5.4%). CONCLUSIONS: The implementation in the clinical microbiology laboratory of the reference method for HCV genotyping allows indeterminate genotype/subtype results to be interpreted and may lead to the identification of previously uncharacterised subtypes.Journal of clinical virology: the official publication of the Pan American Society for Clinical Virology 05/2013; 58(3). DOI:10.1016/j.jcv.2013.05.005 · 3.47 Impact Factor
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ABSTRACT: The hepatitis C virus (HCV) is a globally prevalent human pathogen that causes persistent liver infections in most infected individuals. HCV is classified into seven phylogenetically distinct genotypes, which have different geographical distributions and levels of genetic diversity. Some of these genotypes are endemic and highly divergent, whereas others disseminate rapidly on an epidemic scale but display lower variability. HCV phylogeny has an important impact on disease epidemiology and clinical practice because the viral genotype may determine the pathogenesis and severity of the resultant chronic liver disease. In addition, there is a clear association between the HCV genotype and its susceptibility to antiviral treatment. Similarly to other RNA viruses, in a single host, HCV exists as a combination of related but genetically different variants. The whole formation is the actual target of selection exerted by a host organism and antiviral therapeutics. The genetic structure of the viral population is largely shaped by mutations that are constantly introduced during an error-prone replication. However, it appears that genetic recombination may also contribute to this process. This heterogeneous collection of variants has a significant ability to evolve towards the fitness optimum. Interestingly, negative selection, which restricts diversity, emerges as an essential force that drives HCV evolution. It is becoming clear that HCV evolves to become stably adapted to the host environment. In this article we review the HCV phylogeny and molecular evolution in the context of host-virus interactions.Infection, genetics and evolution: journal of molecular epidemiology and evolutionary genetics in infectious diseases 11/2013; 21. DOI:10.1016/j.meegid.2013.10.021 · 3.26 Impact Factor
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ABSTRACT: The Versant HCV genotype 2.0 assay (LiPA 2.0), based on reverse hybridization, and the Abbott Realtime HCV genotype II assay (Realtime II), based on genotype-specific real-time PCR, have been widely used for analysis of hepatitis C virus (HCV) genotypes. However, their performances for detecting genotype 6 have not been well studied. Here, we analyzed genotype 6 in 63 samples from the China HCV Genotyping Study that were originally identified as genotype 6 using LiPA 2.0. The genotyping results were confirmed by NS5B or core sequence phylogenetic analysis. A total of 57 samples were confirmed as genotype 6 (51 as genotype 6a, five as genotype 6n and one as genotype 6e). Four samples identified as a mixture of genotypes 6 and 4 by LiPA 2.0 were confirmed as genotype 3b. The remaining two samples classified as genotype 6 by LiPA 2.0 were confirmed as genotype 1b, which were intergenotypic recombinants and excluded from further comparison. In 57 genotype 6 samples detected using Realtime II Version 2.00, 47 genotype 6a samples were identified as genotype 6; one 6e sample was misclassified as genotype 1; four 6a and five 6n samples yielded "indeterminate" results. Nine nucleotide profiles in the 5' untranslated region affected the performances of both assays. Therefore, our analysis shows that both assays have limitations in identifying HCV genotype 6. LiPA 2.0 cannot distinguish some 3b samples from genotype 6 samples. Realtime II fails to identify some 6a and all non-6a subtypes and misclassifies genotype 6e as genotype 1.Journal of Clinical Microbiology 08/2014; 52(10). DOI:10.1128/JCM.00882-14 · 4.23 Impact Factor