Predicting differential rifamycin resistance in clinical Mycobacterium tuberculosis isolates by specific rpoB mutations.

Setting Rifampin (RIF)-resistant Mycobacterium tuberculosis (Mtb) is usually assumed to be resistant to all rifamycins. Increasing evidence indicates, however, that some rpoB mutations, detectable by rapid molecular diagnostics, confer resistance to RIF but not rifabutin (RFB), suggesting RFB may be effective for treatment of Mtb with these mutations.