Group A streptococcal myonecrosis: increased vimentin expression after skeletal-muscle injury mediates the binding of...

Area of Science:

• Microbiology
• Cell Biology
• Pathology

Background:

• Invasive group A streptococci (GAS) infections, including necrotizing fasciitis and myonecrosis, are life-threatening and reemerging globally.
• A significant proportion of GAS myonecrosis cases lack a clear entry point, with infections often establishing at sites of prior minor trauma.

Purpose of the Study:

• To investigate the molecular mechanisms by which GAS establishes infection at sites of minor muscle injury.
• To identify specific skeletal muscle cell surface molecules that GAS binds to during infection.

Main Methods:

• Isolation and identification of GAS-binding proteins from skeletal muscle cells.
• In vitro assessment of vimentin expression on injured skeletal muscle cells.
• Analysis of vimentin expression in muscle tissue from a patient with fatal GAS myonecrosis.

Main Results:

• Vimentin was identified as the primary protein on skeletal muscle cells to which GAS binds.
• Vimentin expression was significantly increased on injured skeletal muscle cells in vitro.
• Vimentin was present in muscle tissue from a patient who succumbed to GAS myonecrosis and streptococcal toxic shock syndrome.

Conclusions:

• GAS utilizes vimentin, upregulated on injured muscle, as a key binding protein to initiate infection.
• This molecular interaction provides a mechanism explaining GAS soft-tissue infections at sites of prior minor muscle trauma.
• Understanding this pathway may lead to novel preventive strategies and treatments for severe GAS infections.