Streptococcus pyogenes Transcriptome Changes in the Inflammatory Environment of Necrotizing Fasciitis

Area of Science:

• Microbiology
• Infectious Diseases
• Genomics

Background:

• Streptococcus pyogenes is a primary cause of necrotizing fasciitis.
• Bacterial gene expression changes at infection sites are crucial for pathogenesis but poorly understood in necrotizing fasciitis.
• Previous studies have not provided transcriptomic profiles of S. pyogenes during this infection.

Purpose of the Study:

• To investigate the gene expression profile of Streptococcus pyogenes during necrotizing fasciitis using a mouse model.
• To identify bacterial genes with altered expression in vivo compared to in vitro conditions.

Main Methods:

• A mouse model of necrotizing fasciitis was established.
• Total RNA was isolated from infected hind limbs at 24, 48, and 96 hours postinfection.
• RNA-sequencing (RNA-seq) was performed on Streptococcus pyogenes M1T1 strain 5448.

Main Results:

• 483 bacterial genes showed consistent expression changes during infection compared to in vitro growth.
• 306 genes were enriched, including those involved in virulence, metabolism, and transport.
• Significant upregulation of sagA, speB, and spd genes (encoding toxins) was observed.
• 177 genes were downregulated, including those related to oxidative stress response and cell division.

Conclusions:

• Streptococcus pyogenes exhibits altered metabolism, reduced proliferation, and increased toxin production during necrotizing fasciitis.
• These findings offer critical information for developing novel treatments and vaccines for necrotizing fasciitis.
• The study highlights the importance of virulence factors and metabolic shifts in S. pyogenes pathogenesis.