Mycobacterium abscessus strain variability in preclinical drug development: does it really matter?

New treatment options for Mycobacterium abscessus infections are urgently needed. Since a correlation between MICs and clinical outcomes is not clearly established, potency of novel drugs needs to be evaluated using additional in vitro drug activity assays. Preclinical drug activity assays generally use the M. abscessus type strain ATCC 19977. However, M. abscessus complex entails a genetically and morphologically diverse group, and it is questionable whether drug activity observed against ATCC 19977 is representative of drug activity against clinical M. abscessus isolates.