Brainscape's Knowledge GenomeTM

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


See full index

ID > Streptococci > Flashcards

Streptococci Flashcards

1
Q

How do streptococci differ from staphylococci on gram stain?

A

Strep- gram + chains

Staph- gram + clusters

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

Are streptococci catalase positive?

A

No

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

Certain species of streptococci can either completely or partially hemolyze RBCs. The streptococci are divided into 3 groups based on their specific hemolytic ability, what are these 3 groups?

A

Alpha- partially lyse RBCs (green zone around colony)

Beta- completely lyse RBCs (clear zone around colony)

Gamma- non-hemolytic

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

Streptococci can be classified based on the antigenic characteristics of the C carbohydrate (Lancefield antigen), what 2 pathogenic species of the streptococcal genus do not have Lancefield antigens?

A

Streptococcus pneumoniae

Strep Viridans

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

Streptococci can be classified based on the antigenic characteristics of the C carbohydrate (Lancefield antigen), what pathogenic species of Strep has Lancefield group A antigen?

A

Streptococcus pyogenes

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

What diseases are caused by Streptococcus pyogenes?

A

Strep throat (pharyngitis)

Skin infections (erysipelas, cellulitis, impetigo, necrotizing fasciitis)

Scarlet fever

Toxic shock-like syndrome

Acute rheumatic fever

Post streptococcal glomerulonephritis

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

What components of the streptococcal cell wall are antigenic?

A

C-carbohydrate (Lancefield antigen)

M protein (major virulence factor)

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

What is the function of M protein?

A

Inhibits phagocytosis

Inhibits complement activation

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

Immunity to streptococci infection is based on development of antibodies directed against which protein?

A

M protein (protection is M-type specific)

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

What cells are destroyed by streptolysin O?

A

RBCs

Neutrophils

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

What is the mechanism of action of the streptococcal enzyme streptokinase?

A

Activates plasmin which breaks up fibrin

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

In addition to scarlet fever, what syndrome is mediated by Exotoxin A?

A

Streptococcal toxic shock syndrome

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

What diseases caused by group A Strep directly result from local invasion and/or exotoxin release?

A

Strep throat

Skin infection

Scarlet fever

Toxic shock like syndrome

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

What diseases caused by group A strep are a direct result of delayed antibody mediated responses?

A

Acute rheumatic fever

Post streptococcal glomerulonephritis

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

What test should be ordered to diagnose streptococcal pharyngitis?

A

RADT- rapid antigen detection test

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

A 9 year old child presents with red swollen tonsils and pharynx, and purulent tonsils. A RADT is negative. What is your next step in management?

A

Throat culture- RADT has high specificity, but only moderate sensitivity

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

Antibiotic therapy of streptococcal pharyngitis is directed primarily at preventing what complication?

A

Acute rheumatic fever

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

Skin infections caused by group A Strep can range from folliculitis, pyoderma, cellulitis, erysipelas, and impetigo. These infections can also be caused by S. aureus, thus, what type of therapy should be initiated?

A

Penicillinase resistant penicillin (dicloxacillin)

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

Erysipelas is a superficial bacterial infection of the skin most often caused by beta-hemolytic group A streptococci (Streptococcus pyogenes). It involves the lymphatics of the superficial dermis. Describe the rash associated with this condition.

A

Bright red

Well demarcated border

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

Impetigo is a superficial skin infection caused by inoculation of streptococci through scratches or other breaks in the skin. Describe the rash associated with this condition.

A

Honey crusted plaques, often found around the mouth

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

Detail the clinical findings of scarlet fever.

A

Sandpaper-like scarlet rash which begins on the neck, moves to the trunk, and finally to the extremities.

Strawbery tounge

Fever

22
Q

Define exanthem.

A

Diffuse rash

23
Q

What disease refers to necrotizing fasciitis of the genital region?

A

Fournier gangrene

24
Q

How do you treat severe Streptococcal pyogenes infections?

A

High doses of penicillin

Clindamycin- inhibits bacterial ribosome which shuts down protein production

25
Q

What are the 6 major manifestations of acute rheumatic fever?

A

Fever

Arthritis

Myocarditis

Subcutaenous nodules

Erythema marginatum

Chorea

26
Q

Are group B strep hemolytic?

A

Yes, beta-hemolytic

27
Q

What is another name for group B streptococci?

A

Streptococcus agalactiae

28
Q

What diseases are caused by group B strep?

A

Neonatal: meningitis, pneuomnia, sepsis

29
Q

Neonates with meningitis do not present with the classic sign seen in adults, a stiff neck. What organisms must be covered if you suspect meningitis in the newborn?

A

Streptococcus agalactiae

E. coli

Listeria monocytogenes

30
Q

Two bacteria cause meningitis later in life after maternal antibodies given to the fetus wane and prior to new antibody formation. What are these bacteria?

A

Neisseria meningitidis (Meningococcus)

Haemophilus influenzae

31
Q

What 2 diseases are caused by Viridans group streptococci?

A

Dental infections- S. mutans

Endocarditis- S. sanguinis

32
Q

Contrast the endocarditis due to Viridans group strep to that due to Staph.

A

Viridians group- subacute bacterial endocariditis (SBE), pt develops low grade fevers, fatigue, anemia, heart murmur

Staph- abrupt onset of chills, spiking fever, and rapid valve destruction

33
Q

Group D streptococci were divided into two groups for many years: Group D enterococci and Group D nonenterococci. This classification was changed because recent DNA and rRNA homology studies demonstrated that enterococci are not closely related to other streptococci. How has this altered the classification of group D streptococci?

A

Many former group D streptococci have been reclassified and placed in the genus Enterococcus

34
Q

What are the primary pathogenic enterococci?

A

Enterococcus faecalis

Enterococcus faecium

35
Q

Enterococci are identified in the lab based on unique characterisitcs. What are these characterisitcs?

A

Grow well in 6.5% NaCl

Grow well in 40% bile

Hydrolyze esculin

36
Q

Group D organisms share several features with enterococci, including the group D antigen. How do they differ based on their ability to grow in different solutions?

A

Group D strep can not grow in 6.5% NaCl

Both can grow in 40% bile

37
Q

What diseases are commonly caused by enterococci?

A

UTIs

Biliary tract infections

Bacteremia

Subacute bacterial endocariditis

38
Q

Streptococcus bovis is associated with what malignancy?

A

Colon cancer

39
Q

What Lancefield antigen is associated with Viridans group streptococci?

A

None

40
Q

What diseases are commonly caused by pneumococcus?

A

Adults: meningitis, pneumonaie, sinusitis

Children: otitis media

(Most common cause of these infections)

41
Q

What is the major virulence factor of pneumococcus?

A

Polysaccharide capsule- protects organism from phagocytosis

42
Q

How can you distinguish between Strep viridans and pneumococcus when both are alpha hemolytic, gram + cocci?

A

Viridans- optochin insensitive

Streptococcus pneumoniae- optochin sensitive

43
Q

What is the most common cause of pneumonaie in adults?

A

Strep pneumoniae

44
Q

What does a CXR show in a patient with pneumoniae?

A

Consolidation

45
Q

What bug is the most common cause of bacterial meningitis in adults?

A

Streptococcus pneumoniae

46
Q

Contrast the bacitracin sensitivity of group A and B strep.

A

Group A- bacitracin sensitive

Group B- bacitracin resistant

47
Q

Do Viridans group Strep have a capsule?

A

No

48
Q

What is the Lancefield group of S. bovis?

A

Group D

49
Q

What region of the body are Enterococci part of the normal flora?

A

GI tract

50
Q

Which alpha hemolytic Strep are bile soluble/insoluble?

A

Bile soluble- S. pneumoniae

Bile insoluble- Viridians group strep

ID (28 decks)

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