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The role of iron in the growth and hemolysin (Streptolysin S) production in Streptococcus pyogenes

B B Griffiths1, O McClain

  • 1Oral Roberts University, School of Medicine, Department of Microbiology, Tulsa, Oklahoma 74137.

Journal of Basic Microbiology
|January 1, 1988
PubMed

Insights

Iron concentration critically impacts Streptococcus pyogenes growth and Streptolysin S production. Optimal iron levels are essential for hemolysin yield during bacterial growth phases.

Area of Science:

  • Microbiology
  • Bacterial Physiology
  • Toxinology

Background:

  • Streptococcus pyogenes is a significant human pathogen.
  • Streptolysin S is a key virulence factor produced by S. pyogenes.
  • Iron is an essential nutrient for bacterial growth and metabolism.

Purpose of the Study:

  • To investigate the effect of iron concentration on Streptococcus pyogenes growth.
  • To determine the influence of iron on the in vitro production of Streptolysin S.
  • To characterize the hemolytic activity and stability of Streptolysin S.

Main Methods:

  • Culturing four strains of Streptococcus pyogenes at 37°C.
  • Supplementing a reduced iron medium with varying concentrations of Fe3+-citrate (1-11 µg/mL).
  • Measuring bacterial growth and quantifying Streptolysin S production and hemolytic activity.

Main Results:

  • Bacterial growth and Streptolysin S production were significantly influenced by medium iron concentration.
  • A critical iron concentration of 1.2 µg/mL was identified for optimal hemolysin production.
  • Hemolytic activity peaked during the late exponential to early stationary growth phase and declined thereafter.
  • Bovine, human, and chicken serum demonstrated a stabilizing effect on Streptolysin S.

Conclusions:

  • Iron availability is a crucial factor regulating Streptococcus pyogenes growth and Streptolysin S production.
  • The timing of Streptolysin S production is linked to the bacterial growth cycle.
  • Serum components can stabilize the hemolytic activity of Streptolysin S, suggesting potential roles in vivo.

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