Multidrug-resistant genes of aminoglycoside-modifying enzymes and 16S rRNA methylases in Acinetobacter baumannii strains

Genet Mol Res. 2014 May 16;13(2):3842-9. doi: 10.4238/2014.May.16.9.

Abstract

We examined the distribution of genes of aminoglycoside-modifying enzymes and 16S rRNA methylases in multidrug-resistant Acinetobacter baumannii to explore the association of these genes with drug resistance. Strains isolated from clinical specimens were screened using an automatic microbial identification system, and 9 aminoglycoside-modifying enzyme and 6 16S rRNA methylase genes were analyzed using polymerase chain reaction and verified by DNA sequencing. Next, sequence alignment was carried out using the Chromas software and a susceptibility test was performed using the Kirby-Bauer disk diffusion method. Genes encoding aminoglycoside-modifying enzymes were detected in all 20 strains of multidrug-resistant A. baumannii. The positive rates of aac(3')-I, aac(6')-Ib, ant(3'')-I, and aph(3')-I were 90.0, 90.0, 85.0, and 35.0%, respectively. However, genes encoding 16S rRNA methylases were not positively detected in the 20 strains of multidrug-resistant A. baumannii. The resistance of multidrug-resistant A. baumannii may be associated with aminoglycoside-modifying enzyme genes but not with 16S rRNA methylase genes.

MeSH terms

  • Acetyltransferases / genetics*
  • Acinetobacter baumannii / drug effects
  • Acinetobacter baumannii / enzymology
  • Acinetobacter baumannii / genetics
  • Aminoglycosides / administration & dosage
  • Aminoglycosides / genetics*
  • Anti-Bacterial Agents / administration & dosage
  • Drug Resistance, Multiple, Bacterial / genetics*
  • Humans
  • Methyltransferases / genetics*
  • Microbial Sensitivity Tests
  • RNA, Ribosomal, 16S / genetics*

Substances

  • Aminoglycosides
  • Anti-Bacterial Agents
  • RNA, Ribosomal, 16S
  • Methyltransferases
  • rRNA (adenosine-O-2'-)methyltransferase
  • Acetyltransferases
  • aminoglycoside N(3')-acetyltransferase