Tuberculosis drug resistance testing by molecular methods: opportunities and challenges in resource limited settings.

One of the greatest threats to global tuberculosis (TB) control is the growing prevalence of drug-resistant bacilli. Correctly diagnosing drug-resistant TB patients is more problematic in resource-limited settings as there is no or limited infrastructure for drug susceptibility testing (DST) of TB bacilli. The conventional phenotypic DST method for TB takes weeks before declaring the results and initiating proper anti-TB treatment. Molecular DST offers advantages over the phenotypic methods mainly because of the short turnaround time. This review summarizes the different molecular DST methods for TB and discusses challenges and opportunities in implementing them in resource-limited settings.