Alteration of ribosomal targets by recently described 16S rRNA methyltransferases confers resistance to most aminoglycosides, including arbekacin. Enterobacteriaceae and non-fermentative bacilli acquired through global surveillance programs were screened for the presence of these enzymes on the basis of resistance phenotypes to nine tested aminoglycosides. Subsequent molecular studies determined that 20 of 21 (95.2%) methyltransferase-positive isolates consisted of novel species records or geographic occurrences (North America [armA, rmtB], Latin America [rmtD] and Europe [armA]); rmtC and npmA were not detected. Global emergence of high-level aminoglycoside resistance has become a rapidly changing event requiring careful monitoring.

Fritsche TR, Castanheira M, Miller GH, Jones RN, Armstrong ES.

JMI Laboratories, North Liberty, IA, USA; Achaogen, Inc., South San Francisco, CA, USA; and Tufts University School of Medicine, Boston, MA, USA.