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Spermidine promotes lysozyme tolerance and acid stress resistance in Streptococcus pyogenes M3

Rajashri Banerji1, Parvati Iyer1, Amrita Bhagwat1

  • 1Symbiosis School of Biological Sciences, Symbiosis International (Deemed University), Symbiosis Knowledge Village, Lavale Pune 412115, Maharashtra, India.

Microbiology (Reading, England)
|August 2, 2022
PubMed

Insights

The polyamine spermidine enhances survival of Streptococcus pyogenes under acid stress. This study reveals spermidine alters bacterial cell size and upregulates key genes involved in acid resistance.

Area of Science:

  • Microbiology
  • Pathogen Biology
  • Bacterial Stress Response

Background:

  • Streptococcus pyogenes is a Gram-positive opportunistic pathogen found in the human nasopharynx and skin.
  • Environmental factors like pH and ion availability influence S. pyogenes virulence factor expression.
  • Extracellular polyamines, such as spermidine, are implicated in bacterial pathogenesis and stress resistance.

Purpose of the Study:

  • To investigate the role of the polyamine spermidine in promoting acid stress survival in Streptococcus pyogenes.
  • To understand how spermidine affects S. pyogenes morphology and gene expression under acidic conditions.

Main Methods:

  • Exposure of S. pyogenes to acidic conditions in the presence of spermidine.
  • Analysis of bacterial cell morphology using microscopy.
  • Quantification of gene expression levels, including dltA, mur, pgaD, pepO, and srtA, using quantitative PCR.

Main Results:

  • Spermidine significantly promotes acid stress resistance in S. pyogenes.
  • Spermidine treatment leads to a decrease in S. pyogenes cell size.
  • Spermidine upregulates the expression of the dltA gene and other cell wall-modifying genes (mur, pgaD, pepO, srtA) in S. pyogenes.

Conclusions:

  • The polyamine spermidine enhances Streptococcus pyogenes survival under acid stress.
  • Spermidine influences S. pyogenes morphology and modulates the expression of genes critical for cell wall integrity and acid resistance.
  • Extracellular spermidine may serve as a signaling molecule for S. pyogenes to adapt to host environmental challenges.
Keywords:
adhesioncell membrane modificationinvasionpathogenesispolyaminesvirulence

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