Molecular diagnosis of tuberculosis and drug resistance.

Molecular drug susceptibility testing (MDST) provides rapid diagnosis of tuberculosis (TB) and detection of drug resistance with commendable sensitivity and specificity. MDST reduces unnecessary isolation or treatment, when a negative result for TB is obtained. Because of the possibility of false detection of rifampin resistance by probe-based MDST, confirmation by sequencing is recommended, especially in regions where the prevalence of resistance is low. Revealing mutation identity by sequencing offers opportunities to study drug minimum inhibitory concentrations for each mutation. Such information enables prediction of resistance levels, and may be helpful in formulating optimal regimens, when treatment options are limited.