EX2 Staphylococcus - Daniels

Question 1

Are staph gram + or -

Answer 1

gram +

Question 2

Is staph motile

Answer 2

no; non mitile

Question 3

Does staph form spores

Answer 3

no; non-spore forming

Question 4

What level of oxygen does staph prefer

Answer 4

facultative anaerobes

Question 5

Are staph catalae negative or positive

Answer 5

positive

Question 6

This species staph is coagulase positive

Answer 6

S. aureus

Question 7

This causes the highest burden of disease in people

Answer 7

S. aureus

Question 8

S. aureus is the most common causative agent of what diseases

Answer 8

integumentary and wounds
bacteremia
aspiration pneumonia
UTI
toxic shock syndrome
scalded skin syndrome
food poisoning

Question 9

Where does S. aureus live and where is it most likely to be encountered

Answer 9

lives on and around people; 30-40% prevalence in nasal carriage
muco-cutaneous junctions
hearty environmental survival (clothes, surfaces)
commensal

Question 10

What surfaces does S. aureus enter through

Answer 10

skin/follicles (wounds/ burns/bite marks)

mucosal surfaces

Question 11

What can vary the spread of S. aureus

Answer 11

bacterial inoculum
host immunocompetence
location of infection
bacteremia + immune compromise = trouble

Question 12

What type of population is at risk for severe S. aureus infections

Answer 12

young children/elderly
diabetics
immunosuppressive
HIV
dialysis
IV drug users

Question 13

MSCRAMMs are what

Answer 13

microbial surface components recognizing adhesive matrix molecules
enhance the ability to colonize and invade

Question 14

What is an example of a MSCRAMM and what is so important about it

Answer 14

fibronectin

key player in the ECM function of adhesion

Question 15

True or False

Collagen is a MSCRAMM

Answer 15

True

Question 16

What assists fibronectin in binding

Answer 16

clumping factors; clot formation

Question 17

What is pus

Answer 17

acute suppurative inflammation

pus = neutrophils (PMNs)

Question 18

What do neutrophils do

Answer 18

they are first to arrive
phagocytosis
release toxic oxidative substances (ROS) to kill bacteria
release cytokines for recruitment

Question 19

What is a disadvantage of ROS

Answer 19

they also damage host tissue

sustained inflammation

Question 20

This is a virulence factor of S. aureus that blocks phagocytosis

Answer 20

polysaccharide capsule

Question 21

This is a virulence factor of S. aureus that blocks antibody function

Answer 21

Protein A

Question 22

This is a virulence factor of S. aureus that pop PMNs (lyse neutrophils)

Answer 22

pore-forming toxin

Question 23

This is a specific toxin that is very toxic to PMNs

Answer 23

panton-valentine leukocidin

produced a lot by MRSA

Question 24

This disease causes the layers of the epidermis to separate; caused by exfoliative toxins A and B

Answer 24

staphylococcal scaled skin syndrome

SSSS

Question 25

What are exfoliative toxins

Answer 25

proteases with high-specifitiy for desmosomal proteins in the skin

Question 26

TSST-1 (toxic shock syndrome toxin) is a what

Answer 26

superantigen

Question 27

Superantigens cause what

Answer 27

an unregulated inflammatory response by activating high numbers of CD4 T cells

Question 28

What cytokines are released that influence TSS symptoms

Answer 28

IL-1; fever TNF-α and β; hypertension and capillary leakage IFN-γ, IL-2; rash

Question 29

With an intoxication, not an infection, of staph, what occurs

Answer 29

the toxin is pre-formed in contaminated unrefridgerated food (food poisoning)

Question 30

Many strains of S. aureus secrete what

Answer 30

enterotoxins (A, B, C, D, E)

Question 31

superantigens as enterotoxins cause what

Answer 31

intense paristalsis

Question 32

What is special about the enterotoxin in food poisioning

Answer 32

It is heat stable | cooking the food will kill the bacteria, but no the toxin that has formed

Question 33

These are penicillin binding proteins (PBP) that make the cross links in peptidoglycan

Answer 33

transpeptidsaes | transglycosylases

Question 34

β-lactam antimicrobial agents are inhibitory substrates for what

Answer 34

PBPs | penicillin binds to the protein and inhibits cell wall formation

Question 35

What are the two types of S. aureus that deal with the penicillin family

Answer 35

methicillin susceptible S. aureus (MSSA) | methicillin resistant S. aureus (MRSA)

Question 36

What extra PBP is found in MRSA

Answer 36

PBP2a

Question 37

There is prevalent resistance of what is S. aureus

Answer 37

β-lactam

Question 38

True or False | MRSA frequently carry resistance genes to other drug classes

Answer 38

True!

Question 39

This is used to treat MRSA, or presumed MRSA; although cases of resistant S. aureus have been reported via enterococcus faecium conjugative transposon

Answer 39

vancomycin

Question 40

What makes MRSE so epidemiologically active

Answer 40

In some US regions, 50% of SA infections are MRSA | it is persistent, 21% still carry 4 years post diagnosis

Question 41

True or False | MRSA is more statistically common in the population than in healthcare and professionals

Answer 41

False 1% of the population, 5-15% in healthcare, etc.