Molecular detection of drug-resistant Mycobacterium tuberculosis with a scanning-frame oligonucleotide microarray

The increasing emergence of drug-resistant Mycobacterium tuberculosis poses significant threat to the treatment of tuberculosis (TB). Conventional drug susceptibility testing is time-consuming and takes several weeks because of the slow growth rate of M. tuberculosis and the requirement for the drugs to show antimycobacterial activity. Resistance to TB drugs in M. tuberculosis is caused by mutations in the corresponding drug resistance genes (e.g., katG, inhA, rpoB, pncA, embB, rrs, gyrA, gyrB), and detection of these mutations can be a molecular indicator of drug resistance. In this chapter, we describe the utility of a microarray-based approach exploiting short overlapping oligonucleotides (sliding-frame array) to rapidly detect drug resistance-associated mutations (substitutions, deletions, and insertions) in the pncA gene responsible for resistance ofM. tuberculosis to pyrazinamide (PZA) as an example for this approach. Hybridization of pncA-derived RNA or DNA with the microarray enables easy and simple screening of nucleotide changes in the pncA gene. Sliding-frame microarrays can be used to identify other drug-resistant TB strains that have mutations in relevant drug resistance genes.