Abstract
Introduction Drug-resistant M. tuberculosis (Mtb) strains are a threat to tuberculosis (TB) control worldwide and more advanced, fast and affordable technologies are needed to strengthen laboratory capacity for diagnosis of multidrug resistant (MDR) cases.
Aims The aim of the study is to develop a new rapid diagnostic tool for MDR-TB using a lab-on-chip (LoC) platform suitable for testing other poverty related diseases.
Methods The LoC (In-Check™) provides an all-in-one device for fast amplification of target DNA followed by hybridization on a low-density microarray.
Mtb and most of the clinically relevant mycobacterial species are identified by specific probes targeting the 16S rRNA gene and IS6110. A multiplex PCR was developed to amplify rpoB, katG, and inhA as the most frequently mutated genes involved in resistance to rifampin and isoniazid in species belonging the Mtb complex.
Results The In-Check™ platform was evaluated on isolates and smear positive clinical specimens.
Selected probes allowed identification of Mtb complex, and 10 clinically relevant non-tubercular mycobacterial species, including M. avium and M. intracellulare. The assay detects the following mutations involved in drug resistance: D516V, S531L (rpoB), S315T (katG), and c-15t, t-8c, t-8a (inhA).
Other mutations at codons 533, 526 (rpoB), and 315 (katG) are identified by a negative signal from wild-type probes. Detection limit is 103 bacteria/mL.
Conclusions The In-Check™ platform represents an innovation for its simplicity of use, rapidity and cost-effectiveness and it is particularly suitable for different diagnostics purposes. This is the first device for molecular detection of malaria and TB on the same platform.
- © 2011 ERS
