Novel Plasmid-Mediated 16S rRNA Methylase, RmtC, Found in a Proteus mirabilis Isolate Demonstrating Extraordinary High-Level Resistance against Various Aminoglycosides

摘要: Proteus mirabilis ARS68, which demonstrated a very high level of resistance to various aminoglycosides, was isolated in 2003 from an inpatient Japan. The aminoglycoside this strain could not be transferred recipient strains Escherichia coli CSH-2 and E. HB101 by general conjugation experiment, but DH5α successfully transformed electroporation with the plasmid parent strain, acquired unusually degree against aminoglycosides. Cloning sequencing analyses revealed that presence novel 16S rRNA methylase gene, designated rmtC, responsible for ARS68 its transformant. G+C content rmtC 41.1%, deduced amino acid sequences newly identified methylase, RmtC, shared relatively low identity (≤29%) other plasmid-mediated methylases, RmtA, RmtB, ArmA, have also been pathogenic gram-negative bacilli. Also, RmtC (≤28%) methylases found aminoglycoside-producing actinomycetes. purified histidine-tagged clearly showed methyltransferase activity vitro. located downstream ISEcp1-like element containing tnpA. Several bacilli belonging family Enterobacteriaceae, some them are dispersing worldwide. acceleration among producing such as may indeed become actual clinical hazard near future.