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Flashcards in IDT202 Deck (42):
1

Defining characteristics of S. pyogenes

1) facultative anaerobic
2) gram positive cocci in long chains
3) beta-hemolysis (complete hemolysis)
4) Group A antigen - C-carbohydrate

2

What is S. progenes sometimes referred to as?

Group A Streptococci (GAS)

3

What is lance field Group B (GBS) strep called?

streptococcus agalactiae

4

What are group D streptococci ?

Enterococcus faecalis

5

What is the major antigenic virulence factor in streptococci?

M-protein; it confers resistance to neutrophil and macrophage phagocytosis

6

is a strain lacking M-protein virulent?

no

7

What are the major forms of strep that are discussed?

1) S. pyogenes
2) S. pneumoniae
3) Enterococcus spp
4) S. agalactiae

8

What are the defining features of streptococcus pneumoniae?

1) gram-positive diplococci
2) alpha-hemolysis
3) lancet shape on gram stain
4) polysaccharide capsule (virulence factor)

9

What kind of strep is found in the throat?

1. viridans strep
2. S. pneumoniae
3. S. pyogenes

10

what kind of strep is found in the intestine?

enterococcus faecalis

11

What kind of strep is found on the skin?

Group A, Group B (vagina)

12

GBS

S. agalactiae

13

GAS

S. pyogenes

14

When doing a throat swab, what structure is swabbed?

tonsils

15

How are GAS further sub-divided?

by their M-protein reactivity

16

What types of disease can be caused by M type GAS's?

1) rheumatic fever (rheumatogenic)
2) acute glomerulonephritis (nephritogenic)

17

How des Enterococcus spp look on gram stain?

pairs or chains

18

what are distinguishing characteristics of Enterococcus spp?

1) gamma-hemolysis (non-hemolytic)
2) facultative anaerobes

19

What are 2 bacteria found in the intestines of humans ?

1) E. faecalis (90%)
2) E. faecium (5-10%)

20

what are the clinical syndromes that are caused by S.pyogenes (9)?

1) streptococcal pharyngitis
2) scarlet fever (SF)
3) infectious impetigo
4) erysipelas
5) cellulitis
6) streptococcal toxic-shock syndrome
7) necrotizing fasciitis
8) post-streptococcal acute rheumatic fever (PS-ARK)
9) post-streptococcal acute glomerulonephritis (PS-AGN)

21

What are examples of mild S. progenies infections ?

1) pharyngitis ("strep throat")
2) impetigo - localized skin infection

22

what clinical syndrome caused by GAS is associated with extensive toxin release?

1) scarlet fever
2) toxic shock syndrome

23

What clinical syndrome caused by GAS is associated with invasion and multiplication in the fascia?

necrotizing fasciitis

24

What does 'colonization' mean ?

attachment, growth and multiplication without triggering body defences; no signs and symptoms

25

What does 'disease' mean?

colonization plus body defences active to try to limit further growth/multiplication which leads to signs and symptoms

26

What are the virulence properties of streptococcus pyogenes ?

1) M-protein - anti-phagocytic
2) lipoteichoic acid - adherence
3) Exotoxin A
4) hemolysins
5) hyaluronidase
6) streptokinase

27

What virulence factor of GAS facilitates rapid spread of skin infections?

hyaluronidase because it degrades hyaluronic acid which is the ground substance of subcutaneous tissue

28

How does one treat GAS - strep throat and strep pharyngitis?

penicillin or amoxicillin; macrolide if penicillin allergic

29

How does Rheumatic fever present?

appears several weeks following initial streptococcal infection, inflammation of the joints and/or heart following an episode of streptococcal pharyngitis.

30

what types of infections does S. pneumoniae cause?

upper and lower respiratory infections e.g
1) acute sinusitis
2) otitis media
3) pneumonia
4) bronchitis

31

what does enterococcus normally cause?

1) UTIs (hospital-acquired infections or in the elderly)
2) bacteremia
3) bacterial endocarditis
4) diverticulitis

32

what bacteria is the major cause of upper and lower respiratory infections?

S. pneumoniae

33

How do you treat community acquired pneumonia?

With a macrolide/respiratory fluoroguinolone

34

How do you treat urinary tract infections?

amoxicillin/ampicillin

35

How do you treat invasive disease (intra-abdominal infections, endocarditis)?

ampicillin/gentamicin

36

how do you treat otitis media and sinusitis?

amoxicillin and macrolide if allergic to penicillin

37

what is a super antigen?

exotoxins are a subgroup of super antigens

38

True or False: Colonization is necessary but may not be sufficient for disease development

TRUE

39

How can S. pneumoniae infections be treated?

with oral penicillins, IV penicillins, 2nd and 3rd gen cephalosporins, macrolides, or respiratory fluoroquinolones

40

What antibiotic can treat vancomycin-resistance enterococcus (VRE)?

linezolid or daptomycin

41

What can be used to treat group D strep if patient is beta-lactam allergic?

vancomycin

42

how are enterococcal infections frequently treated>?

with intravenous ampicillin or oral amoxicillin with or without an amino glycoside