A dual molecular beacon approach for fast detection of Mycobacterium tuberculosis

The main objectives of this study were to assess a dual molecular beacon approach for fast detection of Mycobacterium tuberculosis (MT). MT beacon (Tb-B) was designed to target the unique IS6110 (114 bp) and rpoB (215 bp) fragment of the MT (H37Ra) genome, and the two fragments were inserted into the PMD-19T vector after purification, by PCR and sequencing, to construct plasmids. Different dilutions of positive plasmid standards were used for dual molecular beacon RT-PCR of rpoB and IS6110, and standard curves were established.The results show that the dual molecular beacon of rpoB and IS6110 detecting MT was stable (CV is 1.91-2.68 %) with a high amplification efficiency (95.6 %). In addition, the strains of non MT did not generate fluorescence signals, while strains of MT did, indicating that the primers and molecular beacons were specific, and only MT complex was amplified. The linear range was wide (10(3)-10(11) copies/mL), and clinical specimens presenting different bacterial counts can be detected.