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Prophages of Staphylococcus aureus Newman and their contribution to virulence

Taeok Bae1, Tadashi Baba, Keiichi Hiramatsu

  • 1Department of Microbiology, University of Chicago, Chicago, IL 60637, USA.

Molecular Microbiology
|November 3, 2006
PubMed

Insights

Staphylococcus aureus prophages are essential for causing disease. Deleting these phages significantly reduces virulence, highlighting their critical role in staphylococcal infections.

Area of Science:

  • Microbiology
  • Genomics
  • Infectious Diseases

Background:

  • Staphylococcus aureus is a significant human pathogen.
  • Bacteriophages, specifically prophages, can integrate into bacterial genomes and influence host traits.
  • The role of multiple prophages in S. aureus pathogenesis is not fully understood.

Purpose of the Study:

  • To investigate the contribution of four identified prophages (phiNM1-4) in the Staphylococcus aureus Newman strain to bacterial pathogenesis.
  • To determine the impact of individual and combined prophage deletions on S. aureus virulence.

Main Methods:

  • Identification and characterization of four prophages (phiNM1-4) within the S. aureus Newman genome.
  • Genetic manipulation to create S. aureus variants lacking specific prophages (phiNM3 or phiNM1, phiNM2, phiNM4).
  • Assessment of bacterial virulence using a murine model of abscess formation.

Main Results:

  • phiNM1, phiNM2, and phiNM4 (Siphoviridae family) insert at distinct chromosomal locations.
  • phiNM3 encodes beta-haemolysin (hlb) and virulence factors modulating innate immunity (sea, sak, chp, scn).
  • Prophage excision and deletion mutants exhibited organ-specific virulence defects in vivo; complete prophage removal abolished disease causation.

Conclusions:

  • Prophages phiNM1-4 play essential roles in the pathogenesis of Staphylococcus aureus infections.
  • The absence of these prophages leads to significant attenuation of virulence.
  • Prophages are critical determinants of S. aureus disease development.

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