Bacterial Virulence Flashcards
Virulence
The capacity of an organism to produce disease
Virulence factor
The specific part of the pathogen that causes the disease.
Disease caused by a specific component (virulence factor) of a pathogen
Examples of virulence factors
Adhesin Invasin Impedin Aggresin Modulin
Adhesin
Enables binding of the organism to the host tissue
Component of blood clots
Impedin
Enables organism to avoid host defence mechanism
Aggresin
Causes damage to the host directly
Invasin
Enables organism to invade host tissue
Modulin
Induces damage to host indirectly
Staph aureus virulence factors
Fibrinogen binding protein (adhesin)
Leukocidin aka PVL
TSST-1
Staph aureus pathogenicity (which medical conditions is staph aureus associated with?)
Range of medical conditions can occur: TSS wound infection abscess scalded skin syndrome impetigo
Toxic shock syndrome
TSST-1 is a super antigen which is the virulence factor
Symptoms: fever, D+V, sore throat, muscle pain
Signs: macular rash, desquamation
Causative organism: staph aureus, strep pyogenes
PVL
PVL is a virulence factor
Specific toxicity for leukocytes
Clinical presentation: severe skin infections
Strep pyogenes causes which medical conditions (skin)?
impetigo
cellulitis
necrotising fasciitis
