GROUP A STREPTOCOCCI

Question 1

TRUE OR FALSE:
Group A streptococci is NOT part of the normal flora.

Answer 1

TRUE. It is pathogenic to man.

Question 2

MOT:

Answer 2

contaminated droplet

Question 3

“Fever producing bacteria”; flesh eating bacteria:

Answer 3

S. pyogenes

Question 4

Microscopy of S. pyogenes:

Answer 4

gram-positive cocci in chains

Question 5

Culture of S. pyogenes:

Answer 5

small, translucent and smooth; well-defined B-hemolysis

Question 6

Cultivation media:

Answer 6

1. BAP: beta-hemolytic
2. Columbia agar with Colistin and Nalidixic acid (CNA)

Question 7

Will inhibit gram-negative organisms, staphylococci, Bacillus spp., & coryneform:

Answer 7

CNA

Question 8

Major virulence factor; antiphagocytic:

Answer 8

M protein

Question 9

Not present in any other Lancefield groups:

Answer 9

M protein

Question 10

Inhibits the activation of complement:

Answer 10

M protein

Question 11

Associated with rheumatic fever:

Answer 11

Class I M protein

Question 12

Associated with glomerulonephritis:

Answer 12

Class II M protein

Question 13

Mediates epithelial cell attachement:

Answer 13

protein F

Question 14

Bacterial adherence to the respiratory epithelium:

Answer 14

lipoteichoic acid

Question 15

Weakly immunogenic; prevents opsonized phagocytosis; masks its antigens:

Answer 15

hyaluronic acid capsule

Question 16

Causes the lysis of fibrin clots:

Answer 16

streptokinase

Question 17

A protein that binds to plasminogen and activates the production of plasmin:

Answer 17

streptokinase

Question 18

“Oxygen-labile”; highly antigenic:

Answer 18

streptolysin O

Question 19

Responsible for subsurface hemolysis on BAP incubated ANAEROBICALLY:

Answer 19

streptolysin O

Question 20

Causes lysis of WBCs, platelets, tissue cells; induces antibody response:

Answer 20

streptolysin O

Question 21

Streptolysin O is inhibited by:

Answer 21

cholesterol in skin lipids

Question 22

Detects recent infection with S. pyogenes:

Answer 22

Anti-streptolysin O test

Question 23

Detect antibodies to the streptolysin O enzyme produced by group A streptococcus, which is able to lyse RBCs:

Answer 23

Anti-streptolysin O test

Question 24

The most diagnostically important antibodies:

Answer 24

“HAD”
Anti-hyaluronidase
Anti-ASO
Anti-DNAse B

Question 25

"Oxygen-stable"; nonantigenic:

Answer 25

streptolysin S

Question 26

Responsible for subsurface hemolysis on BAP incubated AEROBICALLY:

Answer 26

streptolysin S

Question 27

Causes lysis of WBCs:

Answer 27

streptolysin S

Question 28

Provides more mobility to the pathogen:

Answer 28

deoxyribonucleases (DNAse)

Question 29

Inactivates the chemotactic factor for neutrophils and monocytes:

Answer 29

C5 peptidase

Question 30

It solubilizes the ground substance of mammalian tissue to separate the tissue and spread the organism:

Answer 30

hyaluronidase (spreading-factor enzyme)

Question 31

Act as superantigens activating macrophages and T-helper cells, and induces the release of powerful immune mediators:

Answer 31

Streptococcal pyrogenic exotoxins (SPEs)

Question 32

SPEs are formerly known as:

Answer 32

erythrogenic toxins

Question 33

Mediates rash in scarlet fever:

Answer 33

SPEs

Question 34

"Strep throat"

Answer 34

pharyngitis or tonsilitis

Question 35

Diagnosis of pharyngitis:

Answer 35

throat culture or direct antigen detection

Question 36

A punctuate exanthem overlying diffuse erythema and appears initially on the neck and upper chest:

Answer 36

scarlet fever (scarlatina)

Question 37

It results from a throat infection with a strain of S. pyogenes that carries a lysogenic bacteriophage(T12):

Answer 37

scarlet fever

Question 38

Cardinal signs of Scarlet fever:

Answer 38

1. diffused red rash from the chest to the extremities 2. "strawberry colored" tongue

Question 39

Susceptibility test for scarlet fever:

Answer 39

Dick's test (erythrogenic toxin)

Question 40

Dick's test (+) result:

Answer 40

erythema or redness of the sites

Question 41

Diagnostic test for scarlet fever (current infection):

Answer 41

Schultz Charlton (anti-erythrogenic toxin)

Question 42

Schultz Charlton (+) result:

Answer 42

"blanching phenomenon" - rash fades

Question 43

Skin infection characterized by a defined area of redness (erythema) and accumulation of fluid (edema):

Answer 43

cellulitis

Question 44

Skin infection characterized by painful reddish patches that enlarges and thicken with a sharply defined edges:

Answer 44

erysipelas

Question 45

"Galloping gangrene or flesh-eating bacteria syndrome"

Answer 45

necrotizing fasciitis

Question 46

Categories of necrotizing fasciitis:

Answer 46

Types: 1: mixed infection caused by both anaerobic and aerobic species 2: consists only of group A streptococci 3: gas gangrene and clostridial myonecrosis

Question 47

Characterized by fever, inflammation of the heart, joints, and blood vessels:

Answer 47

rheumatic fever

Question 48

Inflammatory disease of the renal glomeruli; results from the deposition of antigen-antibody complexes:

Answer 48

acute glomerulonephritis or Bright's disease

Question 49

Condition in which the entire organ system shuts down, leading to death:

Answer 49

streptococcal TSS

Question 50

Plays a major role in the pathogenesis of streptococcal TSS:

Answer 50

Spe A

Question 51

Specimen on choice:

Answer 51

pharynx and tonsillar swabs (throat swab)

Question 52

Used to differentiate S. pyogenes from other B-hemolytic group:

Answer 52

bacitracin disk test/taxo A

Question 53

Helpful in the screening for Group A streptococci in throat cultures:

Answer 53

bacitracin disk test

Question 54

Bacitracin disk test (+) result:

Answer 54

any zone of inhibition (susceptible)

Question 55

Organism also susceptible (+) to bacitracin:

Answer 55

Group C and G

Question 56

Sulfamethoxazole and Trimethoprim (SXT) test (+) result:

Answer 56

resistant (Group A and B)

Question 57

SXT test (-) result:

Answer 57

susceptible (Group C)

Question 58

Detects the presence of PYRase or pyrolidonyl-arylamidase enzyme:

Answer 58

PYR test

Question 59

The only B-hemolytic streptococci that is PYR (+):

Answer 59

S. pyogenes

Question 60

PYR test (+) result:

Answer 60

bright/cherry red color (B-naphthylamide) upon adding 0.01% of cinnamaldehyde reagent (p-dimethyl-aminocinnamaldehyde)

Question 61

PYR test (-) result:

Answer 61

no color change

Question 62

Other PYR test (+) organism:

Answer 62

"GAE" Gemella Aerococcus Enterococcus

Question 63

Drug of choice:

Answer 63

Penicillin, Erythromycin