Detection of the high-level aminoglycoside resistance gene aph(2)-Ib in Enterococcus faecium

A new high-level gentamicin resistance gene, designated aph(2)-Ib, was cloned from Enterococcus faecium SF11770. The deduced amino acid sequence of the 897-bp open reading frame of aph(2)-Ib shares homology with the aminoglycoside-modifying enzymes AAC(6')APH(2), APH(2)-Ic, and APH(2)-Id. The observed phosphotransferase activity is designated APH(2)-Ib.