IDT202

Question 1

Defining characteristics of S. pyogenes

Answer 1

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

Question 2

What is S. progenes sometimes referred to as?

Answer 2

Group A Streptococci (GAS)

Question 3

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

Answer 3

streptococcus agalactiae

Question 4

What are group D streptococci ?

Answer 4

Enterococcus faecalis

Question 5

What is the major antigenic virulence factor in streptococci?

Answer 5

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

Question 6

is a strain lacking M-protein virulent?

Answer 6

no

Question 7

What are the major forms of strep that are discussed?

Answer 7

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

Question 8

What are the defining features of streptococcus pneumoniae?

Answer 8

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

Question 9

What kind of strep is found in the throat?

Answer 9

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

Question 10

what kind of strep is found in the intestine?

Answer 10

enterococcus faecalis

Question 11

What kind of strep is found on the skin?

Answer 11

Group A, Group B (vagina)

Question 12

GBS

Answer 12

S. agalactiae

Question 13

GAS

Answer 13

S. pyogenes

Question 14

When doing a throat swab, what structure is swabbed?

Answer 14

tonsils

Question 15

How are GAS further sub-divided?

Answer 15

by their M-protein reactivity

Question 16

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

Answer 16

1) rheumatic fever (rheumatogenic)

2) acute glomerulonephritis (nephritogenic)

Question 17

How des Enterococcus spp look on gram stain?

Answer 17

pairs or chains

Question 18

what are distinguishing characteristics of Enterococcus spp?

Answer 18

1) gamma-hemolysis (non-hemolytic)

2) facultative anaerobes

Question 19

What are 2 bacteria found in the intestines of humans ?

Answer 19

1) E. faecalis (90%)

2) E. faecium (5-10%)

Question 20

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

Answer 20

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)

Question 21

What are examples of mild S. progenies infections ?

Answer 21

1) pharyngitis (“strep throat”)

2) impetigo - localized skin infection

Question 22

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

Answer 22

1) scarlet fever

2) toxic shock syndrome

Question 23

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

Answer 23

necrotizing fasciitis

Question 24

What does ‘colonization’ mean ?

Answer 24

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

Question 25

What does ‘disease’ mean?

Answer 25

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

Question 26

What are the virulence properties of streptococcus pyogenes ?

Answer 26

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

Question 27

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

Answer 27

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

Question 28

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

Answer 28

penicillin or amoxicillin; macrolide if penicillin allergic

Question 29

How does Rheumatic fever present?

Answer 29

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

Question 30

what types of infections does S. pneumoniae cause?

Answer 30

upper and lower respiratory infections e.g

1) acute sinusitis
2) otitis media
3) pneumonia
4) bronchitis

Question 31

what does enterococcus normally cause?

Answer 31

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

Question 32

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

Answer 32

S. pneumoniae

Question 33

How do you treat community acquired pneumonia?

Answer 33

With a macrolide/respiratory fluoroguinolone

Question 34

How do you treat urinary tract infections?

Answer 34

amoxicillin/ampicillin

Question 35

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

Answer 35

ampicillin/gentamicin

Question 36

how do you treat otitis media and sinusitis?

Answer 36

amoxicillin and macrolide if allergic to penicillin

Question 37

what is a super antigen?

Answer 37

exotoxins are a subgroup of super antigens

Question 38

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

Answer 38

TRUE

Question 39

How can S. pneumoniae infections be treated?

Answer 39

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

Question 40

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

Answer 40

linezolid or daptomycin

Question 41

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

Answer 41

vancomycin

Question 42

how are enterococcal infections frequently treated>?

Answer 42

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