Bacterial virulence Flashcards
What is virulence?
Capacity of a microbe to cause damage to the host
What is the most common bacteria found on the skin?
Staphylococcus epidermidis
Everyone has staph epidermidis on their skin.
What is transient carriage?
Transmission of disease by humans. e.g. not washing hands properly, taking notes in inappropriate places.
Where is staph aureus commonly found?
Mouth, nasal carriage, perineum
What is staph epidermidis infections commonly associated with?
Cannulas, catheters
What is an adhesin?
Helps to attach the organism to the host
What is a superantigen?
Binds directly to MHCII complex instead of interacting with clefts on the outside.
What is a toxin?
Single protein component which links to a disease.
What is panton-Valentine Leukocidin?
Toxin which has a specific toxicity for leukocytes
Rare in hospitals but high in community acquired infections.
Especially in MRSA
What is necrotising pneumonia?
Preceded by flu like symptoms
Infection localised to lung and destroys pulmonary tissue.
Progresses rapidly to cause ARDS.
Causes irreversible hypoxaemia and multi-organ failure.
What is toxic shock syndrome toxin 1? (TSST1)
Toxin that is linked with TSS.
TSS can be caused by tampons
How is TSS diagnosed?
Fever of >39
Diffuse macular rash looks like sunburn
Hypotension of organ systems involved.
Which conditions does strep pyogenes cause?
Impetigo, cellulitis, necrotising fascitis.
Classically a sore throat.
What effect does strep pyogenes have on RBC membranes?
Beta haemolytic.
What is the lancefield system?
serotyping of cell wall of a bacterium - group A, B strep
