title: Inhibition of aminoglycoside 6'-N-acetyltransferase type Ib-mediated amikacin resistance by antisense oligodeoxynucleotides.
abstract: Amikacin has been very useful in the treatment of infections caused by multiresistant bacteria because it is refractory to the actions of most modifying enzymes. However, the spread of AAC(6')-I-type acetyltransferases, enzymes capable of catalyzing inactivation of amikacin, has rendered this antibiotic all but useless in some parts of the world. The aminoglycoside 6'-N-acetyltransferase type Ib, which is coded for by the aac(6')-Ib gene, mediates resistance to amikacin and other aminoglycosides. RNase H mapping and computer prediction of the secondary structure led to the identification of five regions accessible for interaction with antisense oligodeoxynucleotides in the aac(6')-Ib mRNA. Oligodeoxynucleotides targeting these regions could bind to native mRNA with different efficiencies and mediated RNase H digestion. Selected oligodeoxynucleotides inhibited AAC(6')-Ib synthesis in cell-free coupled transcription-translation assays. After their introduction into an Escherichia coli strain harboring aac(6')-Ib by electroporation, some of these oligodeoxynucleotides decreased the level of resistance to amikacin. Our results indicate that use of antisense compounds could be a viable strategy to preserve the efficacies of existing antibiotics to which bacteria are becoming increasingly resistant.
mesh_terms: D000123:Acetyltransferases / Q000037:antagonists & inhibitors* / Q000235:genetics / Q000378:metabolism*; D000583:Amikacin / Q000494:pharmacology*; D001483:Base Sequence; D001665:Binding Sites; D002474:Cell-Free System; D015169:Colony Count, Microbial; D024901:Drug Resistance, Multiple, Bacterial / Q000187:drug effects* / Q000235:genetics / Q000502:physiology; D004791:Enzyme Inhibitors / Q000494:pharmacology; D004926:Escherichia coli / Q000187:drug effects / Q000235:genetics; D008969:Molecular Sequence Data; D009690:Nucleic Acid Conformation; D016376:Oligonucleotides, Antisense / Q000235:genetics / Q000378:metabolism / Q000494:pharmacology*; D014176:Protein Biosynthesis; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D016914:Ribonuclease H / Q000378:metabolism; D014158:Transcription, Genetic
chemical_list: D004791:Enzyme Inhibitors; D016376:Oligonucleotides, Antisense; D012333:RNA, Messenger; D000583:Amikacin; D000123:Acetyltransferases; C056532:aminoglycoside N(6')-acetyltransferase; D016914:Ribonuclease H