The newly identified gene confers high-level plazomicin resistance in serovars.

Plazomicin, a next-generation aminoglycoside, was recently approved by the U.S. Food and Drug Administration for the treatment of multidrug-resistant complicated urinary tract infections. It is highly effective against most aminoglycoside-modifying enzymes (AMEs). Here, we report that strains containing the newly identified gentamicin resistance gene () are highly resistant to plazomicin. Heterologous expression of in Δ resulted in plazomicin resistance with minimum inhibitory concentration (MIC) > 256 µg/mL. These findings reveal that GrdA confers significantly higher resistance to plazomicin than the previously known plazomicin-resistant AMEs AA (2)-Ia and APH (2″)-Iva.