Mutations in Ribosomal Protein RplA or Treatment with Ribosomal Acting Antibiotics Activate Production of Aminoglycoside Efflux Pump SmeYZ in Stenotrophomonas maltophilia .

Aminoglycoside resistance in Stenotrophomonas maltophilia is multifactonal, but the most significant mechanism is overproduction of the SmeYZ efflux system. By studying laboratory-selected mutants and clinical isolates, we show here that damage to the 50S ribosomal protein L1 (RplA) activates SmeYZ production. We also show that gentamicin and minocycline, which target the ribosome, induce expression of smeYZ. These findings explain the role of SmeYZ in both intrinsic and mutationally acquired aminoglycoside resistance.