Bacterial Virulence

Question 1

where does staph aureus colonise?

Answer 1

the skin

mucous membranes

Question 2

where is s pyogenes normally found?

Answer 2

the pharynx

the skin

Question 3

what organisms cause toxic shock syndrome?

Answer 3

staph aureus

s pyogenes

Question 4

what are SSTIs?

Answer 4

skin and soft tissue infections

Question 5

name two toxinoses that can be caused by staph aureus

Answer 5

toxic shock syndrome

scalded skin syndrome

Question 6

name five skin presentations of staph aureus infection

Answer 6

rash 
folliculitis 
abscesses 
carbuncle 
impetigo

Question 7

what is folliculitis?

Answer 7

inflammation of hair follicles

Question 8

what is a carbuncle?

Answer 8

a multilocular abscess

Question 9

who is most commonly affected by scalded skin syndrome?

Answer 9

neonates

Question 10

how can a nasal strain of s aureus protect the body?

Answer 10

it can prevent a more aggressive strain from colonising and entering the body

Question 11

which staphylococci is coagulase positive?

Answer 11

staphylococcus aureus

Question 12

what is coagulase?

Answer 12

a virulence factor produced by s aureus that causes blood to coagulate

Question 13

what is staph epidermidis infection associated with?

Answer 13

immunocompromised patients

foreign medical devices such as catheters

Question 14

what are toxinoses?

Answer 14

diseases associated with a single protein component. a toxin or an exotoxin

Question 15

what is TSST-1?

Answer 15

toxic shock syndrome toxin 1

Question 16

describe the symptoms of toxic shock syndrome

Answer 16

rapid progression over 48 hours 
high fever 
vomiting 
diarrhoea 
sore throat 
muscle pain

Question 17

what is the diagnostic criteria for toxic shock syndrome?

Answer 17

fever
diffuse macular rash and desquamation
hypotension
three or more organ systems involved

Question 18

what are adhesins?

Answer 18

a type of virulence factor that facilitate adhesion to other cells/surfaces

Question 19

name three adhesins produced by s aureus

Answer 19

fibrinogen binding
fibronectin binding
collagen binding

Question 20

what is PVL?

Answer 20

panton valentine leukocidin

a group of proteins that forms a complex

Question 21

what does PVL do?

Answer 21

attacks white blood cells

Question 22

what is s aureus containing PVL associated with?

Answer 22

severe skin infections such as necrotising fasciitis

Question 23

what is necrotising pneumonia?

Answer 23

a severe complication of a mild infection, caused by destruction of immune cells

causes ARDS and multi organ failure

Question 24

what is necrotising pneumonia associated with?

Answer 24

PVL positive s aureus

Question 25

what is used to classify strep?

Answer 25

lancefield classification based off of surface antigens (the Lancefield carbohydrate)

Question 26

name some skin infections caused by s pyogenes

Answer 26

impetigo
cellulitis
necrotising fasciitis

Question 27

what lancefield group is s pyogenes in?

Answer 27

group A

Question 28

what is lancefield group A divided into?

Answer 28

further groups according to the M protein

M1, M3 = major serotype
M3, M18 = severe invasive disease