In vitro exposure to clofazimine can select for delamanid and pretomanid resistance in Mycobacterium tuberculosis.

In vitro experiments with Mycobacterium tuberculosis showed that clofazimine exposure selected for delamanid and pretomanid resistance and mutations in fbiA, fbiC, or fbiD-after the acquisition of Rv0678 mutations where this could be determined. Whether this is also possible in vivo and in an Rv0678 wild-type background has to be studied further. Based on the available evidence, however, we propose that nitroimidazole resistance should not be considered an exclusion criterion for the use of clofazimine.