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Methodology for the Study of Horizontal Gene Transfer in Staphylococcus aureus
10:39

Methodology for the Study of Horizontal Gene Transfer in Staphylococcus aureus

Published on: March 10, 2017

Transduction of the plasmid encoding antiseptic resistance gene qacB in Staphylococcus aureus

Hidemasa Nakaminami1, Norihisa Noguchi, Setsuko Nishijima

  • 1Department of Microbiology, School of Pharmacy, Tokyo University of Pharmacy and Life Science, 1432-1 Horinouchi, Hachioji, Tokyo 192-0392, Japan.

Biological & Pharmaceutical Bulletin
|August 2, 2007
PubMed

Insights

The study found that the antiseptic resistance genes qacA/qacB can be transferred via transduction in Staphylococcus aureus. This transfer mechanism poses a risk for community-associated MRSA (C-MRSA) to develop reduced susceptibility to antiseptics.

Area of Science:

  • Microbiology
  • Genetics
  • Antimicrobial Resistance

Background:

  • Plasmid-borne qacA and qacB genes encode multidrug efflux proteins that reduce susceptibility to antiseptic agents like quaternary ammonium compounds.
  • These genes are prevalent in methicillin-resistant Staphylococcus aureus (MRSA) but are rarely found in community-associated MRSA (C-MRSA) strains from impetigo patients.
  • Most MRSA strains causing impetigo carry the exfoliative toxin B (etb) gene on a plasmid.

Purpose of the Study:

  • To investigate the reason for the low prevalence of qacA/qacB plasmids in MRSA isolated from impetigo patients.
  • To determine the transferability of qacA/qacB genes into MRSA strains, particularly those carrying the etb gene.

Main Methods:

  • Performed plasmid transfer experiments using the qacB-encoding plasmid pTZ2162qacB.
  • Utilized transduction and conjugation methods to transfer pTZ2162qacB into S. aureus strain RN4220 and MRSA strains carrying the etb gene.

Main Results:

  • The plasmid pTZ2162qacB was successfully transferred to S. aureus RN4220 via transduction, but not conjugation.
  • pTZ2162qacB could be transduced into MRSA strains that already carried the etb plasmid, demonstrating coexistence.
  • Horizontal transfer of pTZ2162qacB occurs through transduction and is compatible with the etb plasmid.

Conclusions:

  • Horizontal transfer of qacA/qacB genes in MRSA occurs via transduction.
  • The compatibility of qacA/qacB with the etb plasmid suggests a potential risk for the emergence of C-MRSA with decreased antiseptic susceptibility in impetigo patients.

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