Immunology: Strep

Etiology

The cause or origin of a disease.

Streptococcus pyogenes

Type A streptococcus responsible for diseases such as pharyngitis, scarlet fever, and necrotizing fasciitis.

Gram-positive bacteria

Bacteria that stain deep violet under a microscope, indicating a thick peptidoglycan layer in their cell wall.

Virulence factor

A component of a pathogen that contributes to its ability to cause disease.

ASO (Anti-streptolysin O)

An antibody that indicates recent infection with streptococcal bacteria.

Hyaluronidase

An enzyme produced by strep bacteria that breaks down hyaluronic acid, facilitating the spread of infection.

Erythrogenic toxin

A toxin produced by scarlet fever-associated strains of strep that causes rash.

Streptolysin O

An enzyme that creates holes in red blood cell membranes, leading to hemolysis.

Streptokinase

An enzyme that dissolves blood clots by converting plasminogen to plasmin.

Rheumatic fever

A complication of strep infection that can affect the heart after an upper respiratory infection.

Glomerulonephritis

Kidney inflammation that can occur following pharyngitis or skin infections caused by strep.

Toxic Shock Syndrome

A severe condition caused by group A strep that leads to fever, shock, and multi-organ failure.

Streptococcus agalactiae

Group B streptococcus that can cause illness in neonates and adults.

Immunologic manifestations

Responses in the immune system that may occur following a streptococcal infection, including the production of antibodies.

Hemolysis

The breakdown of red blood cells, often in the context of strep infections and observable on blood agar plates.