Hicks, Nathan D.Carey, Allison F.Yang, JianZhao, YanlinFortune, Sarah M.2022-05-272019-04-30Hicks, Nathan D., Allison F. Carey, Jian Yang, Yanlin Zhao, Sarah M. Fortune. "Bacterial Genome-Wide Association Identifies Novel Factors That Contribute to Ethionamide and Prothionamide Susceptibility in Mycobacterium tuberculosis." mBio 10, no. 2 (2019). DOI: 10.1128/mbio.00616-192161-21292150-7511https://nrs.harvard.edu/URN-3:HUL.INSTREPOS:37371796In Mycobacterium tuberculosis, recent genome-wide association studies have identified a novel constellation of mutations that are correlated with high-level drug resistances. Interpreting the functional importance of the new resistance-associated mutations has been complicated, however, by a lack of experimental validation and a poor understanding of the epistatic factors influencing these correlations, including strain background and programmatic variation in treatment regimens. Here we perform a genome-wide association analysis in a panel of Mycobacterium tuberculosis strains from China to identify variants correlated with resistance to the second-line prodrug ethionamide (ETH). Mutations in a bacterial monooxygenase, Rv0565c, are significantly associated with ETH resistance. We demonstrate that Rv0565c is a novel activator of ETH, independent of the two known activators, EthA and MymA. Clinically prevalent mutations abrogate Rv0565c function, and deletion of Rv0565c confers a consistent fitness benefit on M. tuberculosis in the presence of partially inhibitory doses of ETH. Interestingly, Rv0565c activity affects susceptibility to prothionamide (PTH), the ETH analog used in China, to a greater degree. Further, clinical isolates vary in their susceptibility to both ETH and PTH, to an extent that correlates with the total expression of ETH/PTH activators (EthA, MymA, and Rv0565c). These results suggest that clinical strains considered susceptible to ETH/PTH are not equally fit during treatment due to both Rv0565c mutations and more global variation in the expression of the prodrug activators.en-USVirologyMicrobiologyJournal Article2022-05-2710.1128/mbio.00616-19