An rRNA fragment in extracellular vesicles secreted by human airway epithelial cells increases the fluoroquinolone sensitivity of .

Lung infections caused by antibiotic-resistant strains of are difficult to eradicate in immunocompromised hosts such as those with cystic fibrosis. We previously demonstrated that extracellular vesicles (EVs) secreted by primary human airway epithelial cells (AECs) deliver microRNA let-7b-5p to to suppress biofilm formation and increase sensitivity to beta-lactam antibiotics. In this study, we show that EVs secreted by AECs transfer multiple distinct short RNA fragments to that are predicted to target the three subunits of the fluoroquinolone efflux pump MexHI-OpmD, thus increasing antibiotic sensitivity. Exposure of to EVs resulted in a significant reduction in the protein levels of MexH (-48%), MexI (-50%), and OpmD (-35%). Moreover, EVs reduced planktonic growth of in the presence of the fluoroquinolone antibiotic ciprofloxacin by 20%. A deletion mutant of phenocopied this increased sensitivity to ciprofloxacin. Finally, we found that a fragment of an 18S ribosomal RNA (rRNA) external transcribed spacer that was transferred to by EVs reduced planktonic growth of in the presence of ciprofloxacin, reduced the minimum inhibitory concentration of for ciprofloxacin by over 50%, and significantly reduced protein levels of both MexH and OpmD. In conclusion, an rRNA fragment secreted by AECs in EVs that targets the fluoroquinolone efflux pump MexHI-OpmD downregulated these proteins and increased the ciprofloxacin sensitivity of . A combination of rRNA fragments and ciprofloxacin packaged in nanoparticles or EVs may benefit patients with ciprofloxacin-resistant infections. Human RNA fragments transported in extracellular vesicles interfere with drug efflux pumps. A combination of rRNA fragments and ciprofloxacin packaged in nanoparticles or EVs may benefit patients with antibiotic-resistant infections.