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Effects of alpha-phosphoglucomutase deficiency on cell wall properties and fitness in Streptococcus gordonii

Alain Bizzini1, Paul Majcherczyk1, Siham Beggah-Möller1

  • 1Département de Microbiologie Fondamentale, Bâtiment Biophore, Université de Lausanne, Quartier UNIL-Sorge, CH-1015 Lausanne, Switzerland.

Microbiology (Reading, England)
|January 30, 2007
PubMed

Insights

Streptococcus gordonii alpha-phosphoglucomutase (pgm) is crucial for cell wall integrity and virulence. Disrupting the pgm gene impairs growth, viability, and reduces the bacteria's ability to cause experimental endocarditis.

Area of Science:

  • Microbiology
  • Molecular Biology
  • Bacterial Pathogenesis

Background:

  • Streptococcus gordonii is a key commensal bacterium in the human oral cavity.
  • Bacterial cell wall structure and metabolism are critical for survival and virulence.
  • Alpha-phosphoglucomutase (Pgm) is an enzyme involved in carbohydrate metabolism.

Purpose of the Study:

  • To investigate the function of the Streptococcus gordonii alpha-phosphoglucomutase (pgm) gene.
  • To determine the role of Pgm in cell wall composition, bacterial fitness, and virulence.

Main Methods:

  • Gene disruption of the pgm gene in Streptococcus gordonii.
  • Analysis of cell wall muropeptide patterns and teichoic acid content.
  • In vitro growth, viability, and autolytic activity assays.
  • In vivo virulence assessment using a rat model of experimental endocarditis.

Main Results:

  • The pgm transcript is monocistronic and initiated from a sigma(A)-like promoter.
  • pgm mutants showed altered cell wall muropeptide composition and reduced teichoic acid content.
  • In vitro, pgm-deficient strains exhibited reduced growth, decreased stationary-phase viability, and increased autolysis.
  • In vivo, the pgm-deficient strain demonstrated significantly lower virulence in a rat experimental endocarditis model.

Conclusions:

  • The alpha-phosphoglucomutase enzyme (Pgm) encoded by pgm is essential for Streptococcus gordonii.
  • Pgm plays a vital role in maintaining cell wall integrity and bacterial fitness.
  • Disruption of pgm attenuates Streptococcus gordonii virulence, highlighting its potential as a therapeutic target.

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