Acquisition of 16S rRNA methylase gene in XXXX .

@entity801 @entity32791 @entity796 @entity2890 @entity7913 @entity4509 @entity5292 @entity5498 @entity581 @entity4334 @entity10999 @entity526
BACKGROUND: Bacteria develop resistance to @entity581 by producing @entity5292 -modifying enzymes such as acetyltransferase, phosphorylase, and adenyltransferase. These enzymes, however, cannot confer consistent resistance to various @entity581 because of their substrate specificity. Notwithstanding, a @entity796 AR-2 showing high-level resistance (minimum inhibitory concentration >1024 mg/L) to various @entity581 was isolated clinically. We aimed to clone and characterise the genetic determinant of this resistance. METHODS: We used conventional methods for DNA manipulation, susceptibility testing, and gene analyses to clone and characterise the genetic determinant of the resistance seen. PCR detection of the gene was also done on a stock of @entity796 strains that were isolated clinically since 1997. FINDINGS: An @entity5292 -resistance gene, designated rmtA, was identified in @entity796 AR-2. The @entity526 transformant and transconjugant harbouring the rmtA gene showed very high-level resistance to various @entity581 , including @entity4509 , @entity2890 , @entity32791 , @entity10999 , @entity7913 , and @entity801 . The 756-bp @entity4334 rmtA gene encoded a protein, RmtA. This protein showed considerable similarity to the 16S rRNA methylases of @entity5292 -producing actinomycetes, which protect bacterial 16S rRNA from intrinsic @entity581 by methylation. Incorporation of radiolabelled @entity5498 groups into the 30S ribosome was detected in the presence of RmtA. Of 1113 clinically isolated @entity796 strains, nine carried the rmtA gene, as shown by PCR analyses. INTERPRETATION: Our findings strongly suggest intergeneric lateral gene transfer of 16S rRNA methylase gene from some @entity5292 -producing microorganisms to @entity796 . Further dissemination of the rmtA gene in nosocomial bacteria could be a matter of concern in the future.
