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Flashcards in General Microbiology Deck (17)
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1
Q

What microorganism of oral normal flora can cause endocarditis? Why does it occur?

A

Streptococcus viridans

Misplaced

2
Q

What mechanism generally do the viruses use to cause cell damage?

A
  • Main: intracellular replication ▶️ kills cells

- may no noticeable damage ▶️ latent viruses

3
Q

What bacteria can use invasins?

A

Yersinia pseudotuberculosis

4
Q

Specific pathogenic part of LPS, what type of toxin is it? Which organisms have them?

A

Lipid A portion
Endotoxin
Gram (-)

5
Q

Principal mechanism of pathogenicity of the Endotoxin

A

(+) macrophages ▶️ IL-6, IL-1, TNF-alfa ▶️ tissue damage
Bradykinin-induced vasodilation ▶️ endothelial damage ▶️ shock
(+) Hageman factor ▶️ coagulation (DIC)

6
Q

Type of toxins that can be used to produced as vaccine by modification with chemicals and heat. What components do they have? Functions of them.

A

Exotoxin
B component: binding to cell receptor, facilitate internalization of A
A component: active, ADP ribosyl transferase

7
Q

What do the cytolysins do? Examples.

A

Lyse cells from outside by membrane damage

  • lecithinase ▶️ C. perfringes (gangrene, myonecrosis)
  • Alfa toxin ▶️ staphylococcus aureus ▶️ pores in membrane
8
Q

Which exotoxins interferes with 60S ribosomal subunit? Clinical and molecular result.

A
  • shiga toxin ▶️ shigella dysenteriae
  • Verotoxin ▶️ enterohemorrhagic E. coli (EHEC)
  • (-) protein synthesis in eukaryotic cells ▶️ bloody diarrhea
9
Q

Superantigen of staphylococcus aureus, actions of it.

A

TSST-1 ▶️ ⬆️ susceptibility to LPS (endotoxin), shock, capillary leakage

10
Q

Clue to suspect about a microorganism that is a fungus?

A

Complex carbohydrate cell wall (chitin, glucan, manan)

*remember the can be referred as gram (+) because its thick wall retains gram stain

11
Q

What do the enterotoxigenic E. coli toxin (Heat labile toxin) and cholera toxin have in common?

A

ADP ribosylation of Gs subunit of G-protein coupled receptor ▶️ (+) adenylate cyclase ▶️ secretion of fluid and electrolytes from intestinal epithelium

12
Q

Which bacteria possesses a three-component toxin?

A

Bacillus anthracis

*The anthrax toxin is the only medically important three-component toxin. It has one binding component (the protective antigen) and two active components, one an adenylate cyclase toxin and the other the lethal factor.

13
Q

Most common cause of pneumonia in school age children

A

Mycoplasma pneumoniae

14
Q

Biofilm producers microorganisms

A
Staphylococcus epidermidis (catheter-related infections)
Staphylococcus mutans (dental plaque)
15
Q

Urease positive microorganisms

A
Proteus (all species, renal calculi)
Ureaplasma (renal calculi)
Nocardia
Cryptococcus
Helicobacter

*PUNCH (mnemonic)

15
Q

Catalase positive organisms, is a major problem in which disease?

A
All staphylococcus 
Pseudomonas aeruginosa 
Candida 
Aspergillus 
Enterobacteriaceae
- CGD
16
Q

Coagulase positive microorganisms

A

Staphylococcus aureus

Yersinia pestis