EX2 Staphylococcus - Daniels Flashcards Preview

SP14 Microbiology > EX2 Staphylococcus - Daniels > Flashcards

Flashcards in EX2 Staphylococcus - Daniels Deck (41):
1

Are staph gram + or -

gram +

2

Is staph motile

no; non mitile

3

Does staph form spores

no; non-spore forming

4

What level of oxygen does staph prefer

facultative anaerobes

5

Are staph catalae negative or positive

positive

6

This species staph is coagulase positive

S. aureus

7

This causes the highest burden of disease in people

S. aureus

8

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

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

9

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

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

10

What surfaces does S. aureus enter through

skin/follicles (wounds/ burns/bite marks)
mucosal surfaces

11

What can vary the spread of S. aureus

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

12

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

young children/elderly
diabetics
immunosuppressive
HIV
dialysis
IV drug users

13

MSCRAMMs are what

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

14

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

fibronectin
key player in the ECM function of adhesion

15

True or False
Collagen is a MSCRAMM

True

16

What assists fibronectin in binding

clumping factors; clot formation

17

What is pus

acute suppurative inflammation
pus = neutrophils (PMNs)

18

What do neutrophils do

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

19

What is a disadvantage of ROS

they also damage host tissue
sustained inflammation

20

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

polysaccharide capsule

21

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

Protein A

22

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

pore-forming toxin

23

This is a specific toxin that is very toxic to PMNs

panton-valentine leukocidin
(produced a lot by MRSA)

24

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

staphylococcal scaled skin syndrome
SSSS

25

What are exfoliative toxins

proteases with high-specifitiy for desmosomal proteins in the skin

26

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

superantigen

27

Superantigens cause what

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

28

What cytokines are released that influence TSS symptoms

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

29

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

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

30

Many strains of S. aureus secrete what

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

31

superantigens as enterotoxins cause what

intense paristalsis

32

What is special about the enterotoxin in food poisioning

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

33

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

transpeptidsaes
transglycosylases

34

β-lactam antimicrobial agents are inhibitory substrates for what

PBPs
penicillin binds to the protein and inhibits cell wall formation

35

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

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

36

What extra PBP is found in MRSA

PBP2a

37

There is prevalent resistance of what is S. aureus

β-lactam

38

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

True!

39

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

vancomycin

40

What makes MRSE so epidemiologically active

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

41

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

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