Detection of M. tuberculosis using DNA chips combined with an image analysis system

OBJECTIVE: To develop a packaged DNA chip assay (the DR. MTBC Screen assay) for direct detection of the Mycobacterium tuberculosis complex. DESIGN: We described a DNA chip assay based on the IS6110 gene that can be used for the detection of M. tuberculosis complex. Probes were spotted onto the polystyrene strips in the wells of 96-well microtitre plates and used for hybridisation with biotin-labelled amplicon to yield a pattern of visualised positive spots. The plate image was scanned, analysed and interpreted automatically. RESULTS: The results corresponded well with those obtained by conventional culture as well as clinical diagnosis, with sensitivity and specificity rates of respectively 83.8% and 94.2%, and 84.6% and 96.3%. CONCLUSION: We conclude that the DR. MTBC Screen assay can detect M. tuberculosis complex rapidly in respiratory specimens, readily adapts to routine work and provides a flexible choice to meet different cost-effectiveness and automation needs in TB-endemic countries. The cost for reagents is around US$10 per sample.