Brainscape's Knowledge GenomeTM

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


See full index

Micro Q3 > Streptococci > Flashcards

Streptococci Flashcards

0
Q

T/F: Streptococci are obligate anaerobes

A

FALSE - All strep are FACULATIVE ANAEROBES

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

All Streptococci are GM ___ cocci in ______ (arrangement).

A

Gm + in CHAINS

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

Streptococci are catalase ______

A

Negative

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

Group A Streptococci are also referred to as:

A

Streptococcus Pyogenes

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

Group A strep are classified as ____-Hemolytic, which means:

A

Beta hemolytic, means that they completely lyse red cells or produce a large clear zone on blood agar

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

the beta hemolytic streptococci are classified into groups A - O based on _________ _____________. *Bonus, which one is an ‘exception’.

A

They are classified based on complex carbs of the cell wall that act as antigen. Group D is an exception because it is NOT Beta hemolytic. Remember, Group A = Strep Pyogenes

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

Group A strep a further subdivided based on what feature?

A

They are divided based on immunological analysis of their M PROTEIN, of which there are 90+ serotypes.

M Protein appears on the surface of the bacteria.

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

Group A strep are transmitted by __________ and a (small/large) inoculum is required to infect

A

Respiratory droplets; a large inoculum is required. 5-10% of ppl carry strep pyogenes in nasopharynx

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

What are streptolysins and what do they do?

A

These are hemolytic enzymes that cause the beta hemolysis of Group A Strep

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

Streptolysin O:

A

an Oxygen-labile streptolysin that can induce anti-streptolysin-O antibody titers; these titers can be used in diagnosis

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

Streptolysin S:

A

A poorly antigenic streptolysin that is stable in oxygen

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

Streptokinase:

A

An enzyme that triggers blood proteolysis that DESTROYS FIBRIN CLOTS

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

What 2 factors contribute to Strep pyogenes ANTIPHAGOCYTIC activity?

A
  1. Hyaluronic acid capsule - without this they would not be pathogenic!
  2. M Proteins - more M protein = less phagocytosis. Also, Ab against an M protein = immunity to that strain.
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

What are SpeA SpeB and SpeC, and what two clinical presentations are they responsible for

A

These are proteases produced by Strep Pyogenes. They are also considered EXOTOXINs which can act as SUPERANTIGENS.
They cause:
1. The rash of Scarlet Fever
2. Streptococcal Toxic Shock Syndrome

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

5 invasive syndromes caused by strep pyogenes are:

A
  1. Puerperal fever - infected uterus at birth, now uncommon
  2. Acute pharyngitis/tonsilitis - fever, h/a, chills…treat soon to prevent rhematic fever
  3. Impetigo - superficial skin infection, infected via lesion
  4. Erysipelas - severe Cellulitis of dermis + underlying tissue
  5. Necrotizing Fasciitis - highly invasive strain produces a rapidly progressing destructive infection.
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

Rheumatic fever might occur _____ week(s) after an untreated strep infection; Acute glomerulonephritis might occur ___ week(s) later

A

Rheumatic fever - 2-3 weeks after strep throat

Glomerulo - 1 week after skin isolate infections

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

T/F: Penicillin resistance is never a problem with Streptococcus Pyogenes

A

TRUE! All Strep pyogenes are penicillin sensitive!!!

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

T/F: Group A strep are sensitive to bacitracin

A

TRUE. Strep pyogenes are Bacitracin sensitive!

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

T/F: Group B strep have Beta hemolysin

A

TRUE, but it is known to have a smaller zone of hemolysis than Group A

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

T/F: Group B strep are sensitive to Bacitracin

A

FALSE. Group B strep are resistant to bacitracin

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

What group of streptococci (A-O) does Strep. Agalactiae belong to ?

A

Group B

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

Group B strep can be part of the ______ or _______ normal flora

A

Vaginal or Colonic

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

Two patterns of Group B strep infection:

A
  1. Early onset - infection of bay @ birth from vaginal canal -> septicaemia, meningitis, pneumonia, death
  2. Late onset disease - infant to infant spread, has lower mortality
23
Q

Why a re neonattes more susceptible to group B strep @ birth>

A

Lack of maternal Ab

24
Q

Treatment for Group B strep infection:

A

PENICILLIN

25
Q

Group D streptococci are also called:

A

Entercoccus

26
Q

You have a streptococcus that can grow in 6.5% NaCl, what species is it likely to be?

A

Enterococcus faecalis or faecium; enterococci are the only strep that can grow in that conc.

27
Q

Treatment for enterococcus:

A

Because they are resistant to so many antibiotics, VANCOMYCIN is best; however many strains are becoming resistant to Vancomycin.

28
Q

What clinical syndromes are caused by entereococci

A

UTI, wound infection, sepsis. Especially in ELDERLY

29
Q

Viridans Strep are ____ hemolytic

A

ALPHA

30
Q

The species Strep Mutans and Strep sanguis are what from what family

A

Viridans (alpha hemolytic strep)

31
Q

Viridans strep are normal inhabitants of:

A

mouth, nose, pharynx

32
Q

Alpha-hemolytic streptococci are a frequent cause of what syndrome?

A

INFECTIVE ENNDOCARDITIS -> even minor oral trauma from chewing can produce a transient bacteremia -> cocci in blood may adhere to lesion on endocardium, typically a valve, to form a VEGETATION

33
Q

You see a GM + lancet shaped diplococci on a culture; what species is it likely to be?

A

Streptococcus Pneumoniae (Pneumococcus)

34
Q

the QUELLLING reaction can be useful to identify the capsule of what bacterial species

A

Neisseria

35
Q

Pneumococcus produces what protease that aids in its pathogenicity?

A

an IgA protease, which degrades the IgA on the respiratory epithelium, reducing the chances of opsonization and phagocytosis.

36
Q

T/F: pneumococcal pneumonia is the most common form of bacterial pneumonia

A

TRUE; it has a 5-20% fatality rate even when treated. bacteremia in 10-20% of cases

37
Q

How to treat strep pneumoniae:

A

SENSITIVITY TESTING REQUIRED; unlike strep pyogenes, multiple antibiotic resistance is frequent in this species.

38
Q

What vaccines are available for pneumococcus, and who gets each one?

A
  1. Polysaccharide (23 serotype) - used for 65+ or as young as 2 if at risk for disease. This is a T CELL INDEPENDENT VACCINE (poor booster response)
  2. Conjugated (13 serotype) - for peds, is conjugated to Diptheria => causes a T CELL IMMUNE RESPONSE. can prevent pneumococcal meningitis
39
Q

Listeria Monocytogenes is a gm ___ ____, ____-hemolytic, and non/motile.

A

Listeria is a GM + ROD that is MOTILE.

40
Q

There is a risk of _____ contamination by Listeria Monocytogenes because

A

Food conmination common because it can grow at low temps

41
Q

Listera is commonly found in _____ and _____.

It is often transmitted ____ to human.

A

Soil and Water

animal to human txn. (Dairy, meat)

42
Q

Describe the pathogenesis of listeria in 4 basic steps:

A
  1. Invades mononuclear phagocytes
  2. grown intracellularly
  3. moves between host cells via actin filament propulsion
  4. escape from phagosome by secretion of cytolysin, listeriolysin O
43
Q

Clinical syndromes of L. Monocytogenes include:

A

Adult infection w/ meningitis, septicemia, and gastroenteritis
20% fatality rate

44
Q

Prevent L. monocytogenes infection by:

A

avioding raw milk and unprocessed cheese, especially in IMMUNOCOMPRIMISED.

Drink pasturized milk

45
Q

Anthrax Bacillus is a GM ___ _____

A

GM + rod

46
Q

Anthrax bacillus is A/Anaerobic and can/cant form spores

A

IS AEROBIC and Spore forming

47
Q

Typical anthrax transmission is:

A

ANIMAL TO ANIMAL.

Humans are an accidental rare exception

48
Q

Name 3 pathways to human transmission (from animal) for anthrax bacillus

A
  1. Cutaneus
  2. inhalation
  3. Intestional
49
Q

The pathogenicity of anthrax is due to what 3 factors

A

2 exotoxins and 1 protein:

  1. Protective antigen
  2. Edema Factor
  3. Lethal Factor
50
Q

Function of anthrax’s ‘protective antigen’

A

facilitates entry of exotoxins into host. Ab against this protein would be protective

51
Q

Function of anthrax’s ‘edema factor’

A

Adenylate cyclase that enters host cells and is activated by calmodulin

52
Q

Function of anthrax’s ‘lethal factor’

A

disrupts signal transduction for cell division

53
Q

clinical syndrome of Cutaneus anthrax

A

caused by contaminatin for skin by spores. Lesions produce black scab (eschar). untreated may lead to bacteremia.
LEAST SERIOUS PRESENTATION

54
Q

Clinical syndrome of inhaled anthrax

A

Caused by inhaled spores. Happens in 3rd world to wool-sorters. Inhaled spores are phagocytsed by Macrophage -> spores germinate in regional lymph nodes -> MEDIASTINAL LYMPH NODE ENLARGEMENT. RAPIDLY FATAL if untreated.

55
Q

Anthrax prevention

A

Crude vaccine with B. Anthracis proteins for at risk populations.

56
Q

Treatment for anthrax poisoning

A

Ciprofloxacin, tetracycline, penicillin

Micro Q3 (5 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2025 Bold Learning Solutions. Terms and Conditions