Horizontal gene transfer (HGT) events play a pivotal role in the evolution of Mycobacterium abscessus into dominant circulating clones (DCCs), which is capable of causing patient-to-patient transmission. In particular, HGT of the rpoB gene between strains of different subspecies of M. abscessus could also compromise differentiation between strains of M. abscessus. Here, for the first time, using 1,786 M. abscessus genome sequences, we evaluated the global prevalence of M. abscessus strains subjected to rpoB HGT. We found a greater prevalence of M. abscessus subjected to rpoB HGT than to those subjected to hsp65 HGT, which is mainly due to two Rec-mas clones, dominant circulating clone 7 and ST46, which are responsible for dissemination between non-CF patients in Asia. Our data highlight the importance of rpoB HGT in the evolution of M. abscessus, particularly Mycobacterium massiliense, into virulent DCC clones.
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