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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

Lysogenic transfer of group A Streptococcus superantigen gene among Streptococci

Ivo Vojtek1, Zaid A Pirzada, Birgitta Henriques-Normark

  • 11Max F. Perutz Laboratories, University of Vienna, Department of Microbiology and Immunobiology, Vienna, Austria.

The Journal of Infectious Diseases
|January 9, 2008
PubMed

Insights

Bacteriophages can transfer virulence genes between Streptococcus species, enabling adaptation and potentially increasing pathogenicity. This study demonstrates horizontal gene transfer across different M-types of Group A Streptococcus and into other species.

Area of Science:

  • Microbiology
  • Molecular Biology
  • Genetics

Background:

  • Group A Streptococcus (GAS) causes various infections, including streptococcal toxic shock syndrome.
  • Superantigen production by GAS contributes to disease severity.
  • Bacteriophages (viruses that infect bacteria) can carry virulence genes, including those for superantigens.

Purpose of the Study:

  • To investigate the role of superantigen-carrying prophages in GAS virulence.
  • To determine if these phages can transfer virulence genes between different Streptococcus strains and species.

Main Methods:

  • Analysis of a GAS M12 isolate for superantigen-carrying prophages, identifying phi149 encoding superantigen SSA.
  • Sequence analysis of the phi149 phage.
  • Lysogenic conversion experiments using a recombinant phage (phi149::Km(r)) to transfer the phage into various GAS M-serotypes and Streptococcus equisimilis (GCSE) isolates.
  • Back-transfer experiments to confirm phage viability and transferability.

Main Results:

  • The phi149 phage was identified and shown to encode the superantigen SSA.
  • Successful lysogenic conversion was achieved in multiple GAS M-serotypes and GCSE isolates using the recombinant phi149::Km(r) phage.
  • The transferred phage was successfully re-isolated and transferred back to M12 GAS strains, demonstrating horizontal gene transfer capability.

Conclusions:

  • Horizontal transfer of lysogenic phages occurs among GAS, even across different M-type barriers.
  • Toxigenic conversion via lysogeny can happen between different Streptococcus species.
  • This phage-mediated gene transfer may be a mechanism for streptococci to adapt to host environments, potentially increasing virulence.

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