Genomic analysis of global Mycobacterium abscessus isolates reveals ongoing evolution of drug-resistance-associated genes.

Mycobacterium abscessus (MAB) is intrinsically resistant to many antibiotics, but the evolution of acquired drug resistance is poorly understood. We analyzed published genomes of 5,617 clinical MAB isolates from 20 countries and searched for signals of ongoing evolution in 35 drug-resistance-associated genes. Of these, we found 14 genes were subject to positive selection and identified novel mutational sites under selection. Among these, the erm(41) V80I mutation arose exclusively in strains with erm(41) 28T and affected 50.5% (1750/3465) of subsp. abscessus isolates. The study provided evidence that MAB is evolving mutations in drug-resistance-associated genes, and further research is needed to understand the functional consequences of these mutations.