Bacterial Virulence Flashcards
where does staph aureus colonise?
the skin
mucous membranes
where is s pyogenes normally found?
the pharynx
the skin
what organisms cause toxic shock syndrome?
staph aureus
s pyogenes
what are SSTIs?
skin and soft tissue infections
name two toxinoses that can be caused by staph aureus
toxic shock syndrome
scalded skin syndrome
name five skin presentations of staph aureus infection
rash folliculitis abscesses carbuncle impetigo
what is folliculitis?
inflammation of hair follicles
what is a carbuncle?
a multilocular abscess
who is most commonly affected by scalded skin syndrome?
neonates
how can a nasal strain of s aureus protect the body?
it can prevent a more aggressive strain from colonising and entering the body
which staphylococci is coagulase positive?
staphylococcus aureus
what is coagulase?
a virulence factor produced by s aureus that causes blood to coagulate
what is staph epidermidis infection associated with?
immunocompromised patients
foreign medical devices such as catheters
what are toxinoses?
diseases associated with a single protein component. a toxin or an exotoxin
what is TSST-1?
toxic shock syndrome toxin 1
describe the symptoms of toxic shock syndrome
rapid progression over 48 hours high fever vomiting diarrhoea sore throat muscle pain
what is the diagnostic criteria for toxic shock syndrome?
fever
diffuse macular rash and desquamation
hypotension
three or more organ systems involved
what are adhesins?
a type of virulence factor that facilitate adhesion to other cells/surfaces
name three adhesins produced by s aureus
fibrinogen binding
fibronectin binding
collagen binding
what is PVL?
panton valentine leukocidin
a group of proteins that forms a complex
what does PVL do?
attacks white blood cells
what is s aureus containing PVL associated with?
severe skin infections such as necrotising fasciitis
what is necrotising pneumonia?
a severe complication of a mild infection, caused by destruction of immune cells
causes ARDS and multi organ failure
what is necrotising pneumonia associated with?
PVL positive s aureus
what is used to classify strep?
lancefield classification based off of surface antigens (the Lancefield carbohydrate)
name some skin infections caused by s pyogenes
impetigo
cellulitis
necrotising fasciitis
what lancefield group is s pyogenes in?
group A
what is lancefield group A divided into?
further groups according to the M protein
M1, M3 = major serotype
M3, M18 = severe invasive disease
