Tobramycin enhances Mycobacterium abscessus fitness through whiB7 induction

Difficulty treating and eradicating NTM-PD highlights the need for improved understanding of bacterial mechanisms to establish chronic infections. People with the genetic disorder cystic fibrosis (CF) develop bronchiectasis and are the population at highest risk of NTM-PD, caused mainly by Mycobacterium avium or Mycobacterium abscessus (Mabsc).

The majority of people with CF (pwCF) and bronchiectasis develop chronic Pseudomonas aeruginosa airway infections. We hypothesized that antibiotics used to treat P. aeruginosa infections could enhance Mabsc persistence in the CF airway. Here we demonstrate that clinically relevant concentrations of tobramycin, which does not kill Mabsc but is frequently administered to pwCF with chronic P. aeruginosa infections, induced Mabsc expression of whiB7, a transcription factor that activates genes associated with resistance to host defenses.