3 research outputs found
Colorimetric microwell plate reverse-hybridization assay for Mycobacterium tuberculosis detection
Colorimetric microwell plate reverse-hybridization assay for Mycobacterium tuberculosis detection
Direct smear examination using Ziehl-Neelsen staining for pulmonary
tuberculosis (PTB) diagnosis is inexpensive and easy to use, but has
the major limitation of low sensitivity. Rapid molecular methods are
becoming more widely available in centralized laboratories, but they
depend on timely reporting of results and strict quality assurance
obtainable only from costly commercial kits available in high burden
nations. This study describes a pre-commercial colorimetric method,
Detect-TB, for detecting Mycobacterium tuberculosis DNA in which an
oligonucleotide probe is fixed onto wells of microwell plates and
hybridized with biotinylated polymerase chain reaction amplification
products derived from clinical samples. The probe is capable of
hybridising with the IS6110 insertion element and was used to
specifically recognise the M. tuberculosis complex. When combined with
an improved silica-based DNA extraction method, the sensitivity of the
test was 50 colony-forming units of the M. tuberculosis reference
strain H37Rv. The results that were in agreement with reference
detection methods were observed in 95.2% (453/476) of samples included
in the analysis. Sensitivity and specificity for 301 induced sputum
samples and 175 spontaneous sputum samples were 85% and 98%, and 94%
and 100%, respectively. This colorimetric method showed similar
specificity to that described for commercially available kits and may
provide an important contribution for PTB diagnosis