Bacterial Virulence Flashcards
Virulence
The capacity of a microbe to cause damage to the host
Virulence factors
The properties that enable a microorganism to establish itself on or within a host of a particular species and enhance its potential to cause disease
What are 6 main virulence factors?
Adhesion, Invasion, Impeding, Aggressin and Modulin
Adhesion
enables binding of the organism to host tissue
Invasion
enables the organism to invade a host cell/tissue
Impedin
enables the organism to avoid host defense mechanism
Aggressin
cause damage to the host directly
Modulin
cause damage to the host indirectly
What are examples of adhesins?
Fibrinogen-binding protein and collagen-binding protein
What is TSST-1?
Toxic Shock Syndrome Toxin - a toxin released by some staph aureus and strep isolates which cause TSS, resulting in high fever, vomiting, diarrhoea, sore throat, muscle pain
Toxinoses
Any disease or lesion caused by the action of a toxin eg. TSS, staph food poisoning, SSS
What is SSS?
Scalded Skin Syndrome - syndrome is induced by exotoxins A and B, which are released by S. aureus and cause detachment within the epidermal layer, by breaking down the desmosomes. Presents with the widespread formation of fluid-filled blisters
Superantigens
A class of antigens that cause non-specific activation of T-cells resulting in polyclonal T cell activation and massive cytokine release. They act as a defense mechanism against the immune system.
Which toxins are associated with necrotising pneumonia?
PVL (Panton-Valentine Leukocidin) and alpha toxin
Which skin infections are strep pyogenes associated with?
Impetigo, cellulitis and necrosing fasciitis
