atpE Mutation in Mycobacterium tuberculosis Not Always Predictive of Bedaquiline Treatment Failure.

We report the emergence of an atpE mutation in a clinical Mycobacterium tuberculosis strain. Genotypic and phenotypic bedaquiline susceptibility testing displayed variable results over time and ultimately were not predictive of treatment outcome. This observation highlights the limits of current genotypic and phenotypic methods for detection of bedaquiline resistance.