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Biofilm formation by Streptococcus pyogenes: modulation of exopolysaccharide by fluoroquinolone derivatives

Raja Mohmed Beema Shafreen1, Shanmugam Srinivasan, Paramasivam Manisankar

  • 1Department of Biotechnology, Alagappa University, Karaikudi-630 003, Tamil Nadu, India.

Journal of Bioscience and Bioengineering
|July 19, 2011
PubMed

Insights

New fluoroquinolone derivatives effectively inhibit Streptococcus pyogenes biofilm formation, a key factor in antibiotic resistance. These compounds target exopolysaccharide production, offering potential for treating persistent bacterial infections.

Area of Science:

  • Microbiology
  • Infectious Diseases
  • Drug Discovery

Background:

  • Streptococcus pyogenes biofilms contribute to antibiotic treatment failure and chronic infections.
  • Bacterial biofilms exhibit increased tolerance to antimicrobial agents.
  • Fluoroquinolone derivatives have shown efficacy against bacterial pathogens.

Purpose of the Study:

  • To investigate the effect of novel fluoroquinolone derivatives on Streptococcus pyogenes biofilm formation.
  • To assess the impact of these compounds on bacterial exopolysaccharide (EPS) production.

Main Methods:

  • Quantitative biofilm inhibition assays using XTT (2,3-bis (2-methoxy-4-nitro-5-sulfo-phenyl)-2H-tetrazolium-5-carboxanilide).
  • Fourier Transform Infrared (FTIR) spectroscopy to analyze changes in bacterial cell composition.
  • Gas Chromatography-Mass Spectrometry (GC/MS) to identify components of the exopolysaccharide matrix.

Main Results:

  • Specific fluoroquinolone compounds (6a, 6c, 7b, 7c) significantly reduced S. pyogenes biofilm formation by 61-71% at biofilm inhibitory concentrations (BIC).
  • Sub-BIC concentrations (0.5 and 0.25 BIC) also demonstrated significant biofilm reduction (up to 38% and 18%, respectively).
  • FTIR and GC/MS analyses indicated that fluoroquinolones alter exopolysaccharide composition, reducing key sugars like l-glucose and d-mannose.

Conclusions:

  • Fluoroquinolone derivatives are potent inhibitors of Streptococcus pyogenes biofilm formation.
  • These compounds likely exert their effect by disrupting the bacterial exopolysaccharide matrix.
  • The findings suggest a promising therapeutic strategy for combating antibiotic-tolerant S. pyogenes infections.

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