Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

MicroImmuno > Staphylococci and Neisseria > Flashcards

Staphylococci and Neisseria Flashcards

1
Q

The Neisseria species is what type of bacteria?

A

Gram ( - ) diplococci (kidney-bean shaped)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

What type of enzyme does this bacteria produce?

A

Oxidase

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

Where is this species found and is it pathogenic?

A

Many species found in normal flora of the oral cavity and is non-pathogenic.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

What are 2 important pathogenic organisms in this species?

A

Neiserria meningitides and gonorrhoeae

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

How is Neiserria meningitides transmitted?

A

Through respiratory droplets (oral route).

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

What does Neiserria meningitides ferment?

A

Ferments glucose and maltose.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Where is Neiserria meningitides normally found?

A

In the human nasopharynx.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

What are Neiserria meningitides’s virulence factors?

A

Pili, polysaccharide capsule (13 serogroups) which inhibits phagocytosis, endotoxin, IgA protease, which helps with adherence.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

What are the clinical manifestations of this organism?

A

Meningitis (epidemic and sporadic) and Meningococcemia.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

What is the treatment for Neiserria meningitides?

A

Penicillin (tifomycin in epidemic setting).

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

How can infection of Neiserria meningitides bacterium be prevented?

A

Capsular polysaccharide vaccine (A,B,C, W135) or Rifampin chemoprophylaxis in close contacts

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

Which strains of Neiserria meningitides are important for epidemics? Which strain causes sporadic but not epidemic outbreaks?

A

Strains A & C cause epidemics; Strain B causes sporadic settings.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

For Facultative Gram (+) cocci, how do you determine if the bacterium is Streptococci or Staphylococci?

A

Catalase test:
(+) =bubbles, Staphylococci
(–) =no bubbles, Streptococci

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

What does Streptococci look like? Staphylococci?

A

Chains of cocci; Clusters of cocci

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

Which agar plate is more selective: Blood agar or Mannitol Salt agar?

A

Mannitol Salt agar, even though Staphylococci grows on most anything

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

Which test is used to determine if the organism is S. aureus or S. epidermidis?

A

Coagulase test:
aureus = (+)
epidermidis = (-)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

How does the coagulase test work?

A

Coagulase is an enzyme that clots plasma, so if the final result is a jelly like clot it is (+) and if it is liquid it is (-).

18
Q

Staphylococcus epidermidis is Gram ___ cocci grouped in ____, It is catalase ____ , coagulase ____

A

(+); clusters; (+), (-)

19
Q

Where is normally located?

A

In the normal flora of the skin and mucous membranes.

20
Q

What are Staphylococcus epidermidis’ clinical manifestations?

A

Becomes virulent when infections of IV catheters and prosthetic devices occur.

21
Q

Staphylococcus aureus is Gram ___ cocci grouped in ____, It is catalase ____ , coagulase ____

A

(+); clusters; (+); (+)

22
Q

What % of normal adults are nasal carriers? What % never colonize, intermittently colonize and persistently colonize?

A

10-40%; 20%; 50%; 30%

23
Q

Which group of people has a higher carrier rate of S. aureus?

A

Nurses, physicians, and IV drug abusers (This is a Nosocomial pathogen).

24
Q

What is the most common form of transmission and best way for prevention for S. aureus?

A

Person to person by hands; wash your hands!

25
Q

Can S. aureus break through intact skin?

A

No

26
Q

What is Chronic Granulomatous Disease?

A

An immunodeficiency disease where PMNs can engulf the organism, but can’t kill it and so repeated infections occur.

27
Q

What are the virulence factors of S. aureus?

A

Capsule + cell wall components

28
Q

What components of the cell wall cause S. aureus to be virulent?

A

Peptidoglycan, Protein A and Teichoic acid

29
Q

How does Protein A bind to its host and what are its effects?

A

Binds to Fc region of Ab molecule, inhibiting phagocytosis

30
Q

What enzymes does S. aureus produce?

A

Coagulase, catalase and cytotoxic enzymes

31
Q

What 2 important cytotoxic enzymes are produced by S. aureus and what do they do?

A

Alpha toxin – Hemolysom

Luekicidin – Kills PMNs

32
Q

What exotoxins does S. aureus produce?

A

Enterotoxin, Toxic Shock Syndrome Toxin, and Exfoliatin

33
Q

List the clinical manifestations of Staphylococcal infections.

A

Abscess: a collection of pus (PMNs)
Skin Infections: Folliculitis, Furu/Carbuncle, Impetigo, Cellulitis
Systemic Infections: Bacteremia, Endocarditis, Septic Arthritis, Pneumonia
Toxic Mediated Infections: Scalded Skin syndrome, Toxic Shock syndrome, Food poisoning

34
Q

What is folliculitis?

A

Superficial lesion in a hair follicle

35
Q

What is a faruncle/carbuncle?

A

Deeper infection involving single hair follicle (furuncle-boil) or multiple hair follicles (carbuncle)

36
Q

What toxin causes scalded skin syndrome? Toxic Shock syndrome? Food Poisoning?

A

Scalded Skin Syndrome - Exfoliatin
Toxic Shock Syndrome - TSST-1
Food poisoning - Enterotoxins

37
Q

In Scalded Skin syndrome, what does Exfoliatin cause? What is the most serious consequence of this toxin?

A

A sunburn like rash followed by separation of epidermal cells; can lead to secondary infection due to the gaps in epidermal cells

38
Q

Define superantigen? How does TSST-1 act like a superantigen?

A

A superantigen causes the release of large amounts cytokines by activating a lot of T cells; TSST-1 causes IL-1, IL-2 and TNF to be released by activating T cells outside of their binding sites.

39
Q

What causes illness in food poisoning?

A

Intoxication by 6 types of exotoxins (A-F), not infection and therefore short incubation period (2-6 hours).

40
Q

Is Staphylococcus very resistant to antibiotics?

A

Yes, extremely resistant with 85% of strains resistant to penicillin.

41
Q

How are Staphylococcal infections treated?

A

Beta-lactamase resistant penicillin – Nafcillin or in last line of defense Vancomycin.

MicroImmuno (13 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions