Immunology - Streptococcal Infections

Streptococcus pyogenes

The most common causative agent of pharyngitis, also known as strep throat.

Necrotizing fasciitis

A severe skin infection caused by Strep pyogenes that leads to tissue death.

M protein

A major virulence factor of Strep pyogenes that inhibits phagocytosis and helps the bacteria adhere to host cells.

Streptolysin O

An oxygen-labile enzyme that binds to red blood cell membranes, causing cell lysis and is antigenic.

Streptolysin S

An oxygen-stable enzyme responsible for beta-hemolysis in blood agar, but is not antigenic.

Hyaluronidase

An enzyme produced by Strep pyogenes that breaks down hyaluronic acid in host connective tissue.

Erythrogenic toxin

A toxin produced by some strains of Strep pyogenes that causes the rash associated with scarlet fever.

Acute rheumatic fever

A serious complication of untreated strep throat, potentially affecting the heart.

Post-streptococcal glomerulonephritis

A kidney disease that can occur after a Strep pyogenes infection, particularly strep throat.

Group B Streptococcus (Streptococcus agalactiae)

A gram-positive coccus that can cause severe illness in newborns and is screened in pregnant women.

Beta-hemolysis

The complete lysis of red blood cells in blood agar, characteristic of certain Streptococcus species.

Streptococcal toxic shock syndrome

A severe condition caused by invasive streptococci, leading to systemic shock and organ failure.

Culture swab

A method used to collect samples from the throat to diagnose Strep infections.

Serological tests

Tests used to detect the presence of antibodies against streptococcus, confirming infections.

Impetigo

A skin infection caused by Strep pyogenes characterized by red, swollen lesions that can ooze and crust.

Pharyngitis

Inflammation of the throat, commonly caused by Strep pyogenes and typically referred to as strep throat.

Septic arthritis

A joint infection that can occur as a complication of strep throat.

DNase

An enzyme produced by Streptococcus pyogenes that degrades DNA within the host.

Epidemiology of Streptococcus

Studies how infections spread, commonly seen in school-aged children through respiratory droplets.

Toxin-producing bacteria

Bacteria that produce harmful substances that can cause disease and tissue damage.

Symptoms of scarlet fever

Fever, sore throat, and a characteristic red rash resulting from infection with erythrogenic toxin.