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 5617 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 that were subject to positive selection, and we 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.