Determination of MIC Distribution and Epidemiological Cut-Off Values for Bedaquiline and Delamanid in Mycobacterium tuberculosis Using MGIT 960/TB eXiST

Bedaquiline and delamanid have recently been approved by the regulatory authorities for treatment of multidrug-resistant tuberculosis (MDR-TB). Antimicrobial susceptibility testing is not established for either substance. On the basis of MGIT 960/TB eXiST we determined a mean bedaquiline MIC of wild-type strains of 0.65 mg/L (median 0.4 mg/L) and an epidemiological cut-off (ECOFF) of 1.6 mg/L; for delamanid a mean wild-type MIC of 0.013 mg/L (median 0.01 mg/L) and an ECOFF of 0.04 mg/L was determined