Acinetobacter baumannii GC2 Sublineage Carrying the aac ( 6 ′)- Im Amikacin, Netilmicin, and Tobramycin Resistance Gene Cassette

Aminoglycosides are important therapeutic options for treatment of Acinetobacter infections. Here, we show that a little-known aminoglycoside resistance gene, aac(6′)-Im ( aacA16 ), that confers amikacin, netilmicin, and tobramycin resistance has been circulating undetected for many years in a sublineage of A. baumannii global clone 2 (GC2), generally with a second aminoglycoside resistance gene, aacC1 , which confers resistance to gentamicin.