Comparison of a Nucleic Acid Sequence-based Amplification (NASBA) and real-time reverse transcriptase PCR methods for detection of Toxoplasma gondii in rat blood samples

Abstract

The numbers of RNA amplification methods for detection of <em>Toxoplasma </em>spp<em>.</em> are increasing, however comparative studies on the performance of these different assays are lacking. The aim of this study was to compare two molecular assays for detection and quantification of <em>Toxoplasma </em>spp. in blood samples collected from experimentally infected rats. A set of specific primers and beacon probe were selected from the B1 rRNA gene of <em>Toxoplasma</em>. The assays using real-time detection proved to be both sensitive and specific. Nucleic acid sequence-based amplification (NASBA) method for detection of <em>Toxoplasma </em>spp. have advantages regarding sensitivity and potential quantitative population dynamics of <em>Toxoplasma gondii</em> in comparison with the RT-PCR method, but it is not often routinely used at present. NASBA had a detection limit of 1 parasite/ml of blood, while RT-PCR detected 10 parasites/ml. The results of real-time NASBA can be obtained 12h earlier. Therefore, sooner than the ordinary real-time RT-PCR the use of real-time NASBA is preferred to the ordinary real-time RT-PCR.