Investigation of aminoglycoside modifying enzyme genes in methicillin-resistant staphylococci

Microbiol Res. 2006;161(1):49-54. doi: 10.1016/j.micres.2005.05.002. Epub 2005 Jul 5.

Abstract

Methicillin-resistant staphylococci may also be resistant to some other antibiotics as well as beta-lactams. In this study, co-existence of resistance to methicillin and aminoglycosides was genetically investigated in staphylococci. A total of 50 staphylococci from in-patients, 17 Staphylococcus aureus and 33 coagulase negative staphylococci (CNS) that contained mecA (gene encoding PBP 2a, an altered penicillin-binding protein) determined by polymerase chain reaction (PCR) were included in the study. Aminoglycoside modifying enzyme (AME) genes were investigated using multiplex-PCR. Aminocyclitol-6'-acetyltransferase-aminocyclitol-2''-phosphotransferase [aac(6')/aph(2'')] gene (encoding bifunctional acetyltransferases/phosphotransferases) was determined in 66% of the isolates, aminocyclitol-4'-adenylytransferase (ant(4')-Ia) gene (encoding phosphotransferases) in 24%, and aminocyclitol-3'-phosphotransferase (aph(3')-IIIa) gene (encoding nucleotidyltransferases) in 8%. Two isolates contained all these three genes. Thirty-six (72%) isolates had at least one of these genes. Three CNS and one S. aureus isolates sensitive to oxacillin had the mecA gene. In conclusion, a high rate of aminoglycoside resistance was determined in methicillin-resistant staphylococci. The aac(6')/aph(2'') was the most frequently detected.

MeSH terms

  • Acetyltransferases / chemistry
  • Acetyltransferases / genetics
  • Acetyltransferases / metabolism
  • Aminoglycosides / pharmacology*
  • Bacterial Proteins / genetics
  • DNA, Bacterial / chemistry
  • DNA, Bacterial / genetics
  • Genotype
  • Humans
  • Methicillin Resistance / genetics*
  • Penicillin-Binding Proteins
  • Phosphotransferases (Alcohol Group Acceptor) / chemistry
  • Phosphotransferases (Alcohol Group Acceptor) / genetics
  • Phosphotransferases (Alcohol Group Acceptor) / metabolism
  • Polymerase Chain Reaction
  • Staphylococcal Infections / microbiology
  • Staphylococcus / drug effects*
  • Staphylococcus / enzymology*
  • Staphylococcus / genetics
  • Staphylococcus / growth & development

Substances

  • Aminoglycosides
  • Bacterial Proteins
  • DNA, Bacterial
  • Penicillin-Binding Proteins
  • mecA protein, Staphylococcus aureus
  • 6'-aminoglycoside acetyltransferase-2''-aminoglycoside phosphotransferase
  • Acetyltransferases
  • Phosphotransferases (Alcohol Group Acceptor)