In Vitro and Animal Studies of Human Natural Killer Cell-Derived Exosomes for the Treatment of Otitis Media.

Otitis media is an infection of the middle ear mainly caused by bacteria, and current treatments rely heavily on antibiotics. However, the emergence of antibiotic-resistant bacterial strains seriously affects their efficacy. In our study, we found that extracellular vesicles (EVs) derived from human natural killer cells (NKs) inhibit the proliferation of both standard and levofloxacin (LVX)-resistant strains of Staphylococcus aureus in a dose-dependent manner. Moreover, compared to LVX, EVs were more effective at reducing effusion and rescuing hearing thresholds in animal models. For LVX-sensitive strains, EVs were significantly more effective in terms of curative time but not curative rate. For LVX-resistant strains, EVs were significantly more effective in terms of both curative rate and curative time when applied alone or applied jointly with LVX. In summary, we found that NK EVs are highly effective in treating otitis media, providing an alternative approach for treating this common disease.