Development, Evaluation, and Standardization of a Real-Time TaqMan Reverse Transcription-PCR Assay for Quantification of Hepatitis A Virus in Clinical and Shellfish Samples

• Published in: Applied and Environmental Microbiology 2006-06, Vol.72 (6), p.3846-3855
• Main Authors: Costafreda, M. Isabel, Bosch, Albert, Pintó, Rosa M
• Format: Article
• Language: English
• Subjects: 5' noncoding region; Animals; Base Sequence; Biological and medical sciences; clams; Consensus Sequence; disease diagnosis; DNA primers; DNA probes; food contamination; food microbiology; Fundamental and applied biological sciences. Psychology; Genomics; Hepatitis A virus; Hepatitis A virus - genetics; Hepatitis A virus - isolation & purification; Humans; internal fluorescent probe; Mengovirus; microbial contamination; Microbiology; Molecular Sequence Data; Public Health Microbiology; quantitative analysis; Reproducibility of Results; reverse transcriptase polymerase chain reaction; Reverse Transcriptase Polymerase Chain Reaction - methods; Ribonucleic acid; RNA; RNA, Viral - genetics; RNA, Viral - isolation & purification; Shellfish; Shellfish - virology; viral hepatitis; Viruses
• ISSN: 0099-2240; 1098-5336
• DOI: 10.1128/aem.02660-05

A standardized real-time reverse transcription-PCR (RT-PCR) assay has been developed for an accurate estimation of the number of genome copies of hepatitis A virus (HAV) in clinical and shellfish samples. Real-time procedures were based on the amplification of a fragment of the highly conserved 5' noncoding region and detection through an internal fluorescent probe, including TaqMan and beacon chemistries, in one- and two-step RT-PCR formats. The best performance in terms of sensitivity and reproducibility was achieved by a one-step TaqMan RT-PCR, with a sensitivity enabling the detection of 0.05 infectious unit and 10 copies of a single-stranded RNA (ssRNA) synthetic transcript. Standard reagents, such as a mengovirus strain and an ssRNA transcript, were employed as controls of nucleic acid extraction and RT-PCR, respectively. The test proved to be highly specific after a broad panel of enteric viruses was tested. Sequence alignment of target regions of the primers and probe proved them to be adequate for the quantification of all HAV genotypes. In addition, a quasispecies analysis of the mutant spectrum indicated that these regions are not prone to variability, thus confirming their robustness.