Exam 5—COVID and Staphylococcus Flashcards

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1
Q

SARS & MERS mortality

A

10%
35%

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2
Q

— COVID protein binds ——-

A

S1
ACE-2 receptor

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3
Q

first covid gene translated

A

replicase

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4
Q

negative strand copy of ssRNA is used to make…

A

(1) more positive strand copies
(2) small RNAs for spike + membrane + envelope + nucleocapsid proteins (S + M + E + N)

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5
Q

2 cytokine related COVID syndromes

A

cytokine storm (IL6)
cytokine release syndrome

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6
Q

cytokine release syndrom sx

A

fever and organ dysfunction - may have hemoptysis, renal failure, diarrhea

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7
Q

Lopinavir, ritonavir, molnupiravir, paxlovid

A

covid protease inhibitors

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8
Q

Hydroxychloroquine, ivermectin

A

no value

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9
Q

Alpha-interferon

A

covid viral inhibitor

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10
Q

remdesivir

A

inhibits covid RNA polymerases

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11
Q

Regeneron, strovimab

A

covid monoclonal antibody against spikes

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12
Q

Tolicizumab

A

covid monoclonal antibody against IL-6 receptor

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13
Q

dexamethasone

A

steroid to reduce covid inflammation

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14
Q

covid surface disinfectants

A

Metal surfaces antimicrobial (especially copper)
2% bleach
70% ethanol/rubbing alcohol
0.5% H2O2

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15
Q

staph are Cat —

A

Pos

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16
Q

coag-pos staph (5)

A

S. aureus
S. hyicus
S. intermedius
S. pseudintermedius
S. lutrae

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17
Q

purpose of coagulase

A

Blood clots protect organisms from phagocytosis, antibody binding, and complement activation

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18
Q

core genome

A

genome shared by 80-90% of species

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19
Q

paragenome

A

complete set of genes found in species; core genome + strain specific genes

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20
Q

MSCRAMM

A

microbial surface components recognizing adhesive factors

21
Q

MSCRAMM tropisms (5)

A

fibronectin binding, collagen binding, laminin binding, vibronectin binding, elastin binding

22
Q

clumping factor function

A

binds fibrinogen, causing clumps of plasma
also binds factor I, which degrades C3Bb

23
Q

abscess progression

A

Microbe associated molecular patterns (MAMPs) elicit cytokine response via TLRs
Coagulase builds a “cage” around the infection, creating a hard local infection
Toxin expression occurs

24
Q

tst gene

A

TSST-1

25
Q

TSST-1

A

Causes nonspecific T-cell activation, which causes release of large amounts of IL-1 and TNF-𝛼

26
Q

sx of TSS

A

fever, hypotension, n/v/d; multiple organs involved

27
Q

TSS mortality

A

65%

28
Q

responsible for food poisoning

A

staphylococcal enterotoxins (SEA and SEB)

29
Q

entA and entB

A

SEA and SEB

30
Q

enterotoxins made by —-% of S. aureus

A

30-50%

31
Q

Exfoliative toxin (Ets)

A

cleaves desmoglein-1 which is a cadherin that holds keratinized skin layer to basal layer of epidermis

scalded skin syndrome

32
Q

bullous impetigo

A

Ets toxin (scalded skin)

33
Q

Panton-Valentine Leukocidin
LukF and LukS

A

polymerize and form pores in membranes of WBCs

34
Q

Staphylokinase (Sak)

A

binds plasminogen and activates it to cleave fibrin in an uncontrolled way

Bacteria are allowed to escape clot and spread to blood stream

35
Q

Sak causes circumvention of…

A

Regulation by PAI-1 and antiplasmin

36
Q

Staphylococcal alpha toxin
Hla

A

Integrates into membranes of host cells, causing pores
Causes alpha hemolysis

37
Q

MSCRAMM attachment
C-terminus has a conserved ——- amino sequence

this binds to the ——-, which then passes it off to amide of one of the ——–

this forms a peptide bond between the (above) and the MSCRAMM

A

LPXTG
sortase
glycine

38
Q

housekeeping sortase

A

sortase A

39
Q

iron acquisition sortase

A

sortase B

40
Q

pilus sortase

A

sortase C

41
Q

spore formation sortase

A

sortase D

42
Q

Fibronectin-binding protein (FnBP)
species

A

Covering bacterial cell with fibronectin makes it “look” like the host

S. aureus

43
Q

Protein A

A

Binds Fc of IgG, preventing opsonization

Can also bind Fc of membrane-bound antibody, like IgD or IgM, which triggers apoptosis in the B-cell

44
Q

alternative lactamase used in some staph, which usually have no such activity

A

BlaZ lactamase

45
Q

main virulence mechanism of S. epidermidis

A

biofilms

46
Q

opportunity for S. epidermidis to infect

A

Catheters, prosthetics, pacemakers, microscopic tears in surgical gloves

47
Q

S. epidermidis capsule production of ——- leads evasion of immune system

action

A

poly-γ-glutamic acid

Protects from osmotic stress
Contributes to biofilm formation
Blocks phagocyte action
Prevents action of antimicrobial peptides
Combines with liberated DNA to form biofilm

48
Q

Phenol-soluble modulins (PSMs)
δ-toxin

species, action

A

Made by S. aureus, S. epidermidis, S. haemolyticus

Cause inflammation
Detergent like action disrupts cell membranes
Can allow for phagosome escape

49
Q

only produces phenol-soluble toxins

A

S. epidermidis