[Fundamental studies on "M. TB probe assay kit" for the identification of Mycobacterium tuberculosis]

DNA probe assay kit for the identification of Mycobacterium tuberculosis was evaluated. This kit is based on beads capture method and using a 20 well assay tray. The culture isolate is suspended with 0.5 ml sterilized water in the tube containing phi 3 mm glass beads for dispersion, transferred to a well of the assay tray. After lysation and adsorption of the nucleic acids to the capture bead, 125I-DNA probe specific for the M. tuberculosis is added to the sample and hybridized for 1 hour at 65 degrees C. Hybridized probe trapped on the capture bead is quantitated using a gamma counter. This hybridization assay kit can detect more than 1 x 10(5) bacteria per assay. Using the control DNA (synthesized oligonucleotide complementary to the probe sequences) and suspension of the culture isolates, the intra assay C.V. value was 4.3% and 5.2% respectively. To compare this probe assay kit with the conventional culture identification method, a total of 144 culture isolates were examined. This test for the M. tuberculosis had 99.3% agreement with the conventional identification procedures, and demonstrated 100% sensitivity and 98.2% specificity. The suspension of culture isolates can be stocked by freezing, the samples can be assayed together when they have accumulated instead of every day. As shown in the above, this assay kit demonstrates a high level of specificity and sensitivity.(ABSTRACT TRUNCATED AT 250 WORDS)