Exam 1 Lecture 10

Question 1

What group does Streptococcus pyogenes fall under?

Answer 1

Group A

Question 2

Name some important characteristics of S. pyogenes (think structure, hemolysis, enzyme presence)

Answer 2

• Gram positive cocci that comes in pairs and chains
• beta hemolytic
• catalase negative

Question 3

Where can S. pyogenes be found as part of the normal microbiota?

Answer 3

skin and nasopharynx

Question 4

How does S. pyogenes spread? (2 things)

Answer 4

1. respiratory droplets

2. direct contact

Question 5

________ ____ and ______ _ bind epithelial fibronectin, which enhances bacterial adherence and entry into human cells

Answer 5

lipoteichoic acid

protein F

Question 6

What protein is a scaffold for lipoteichoic acid and is important in binding keratinocytes?

Answer 6

M protein

Question 7

What does the M protein bind to?

Answer 7

fibrinogen

Question 8

The M protein is a key virulence determinant. What makes it increase virulence of S. pyogenes? (4 things)

Answer 8

1. limits complement deposition via the alternative pathway
2. it is anti-phagocytic
3. sequesters and neutralizes antimicrobial peptides
4. M-like proteins

Question 9

What kind of capsule does S. pyogenes have?

Answer 9

Hyaluronic acid capsule

Question 10

What is hyaluronic acid a major component of?

Answer 10

connective tissue (thus it disguises itself by blending in)

Question 11

What is the role of C5a peptidase is S. pyogenes?

Answer 11

It inactivates c5, which normally functions to recruit host phagocytes

Question 12

List the types of Streptococcal pyrogenic exotoxins

Answer 12

SPE A, B, C

Question 13

Out of the 3 SPEs, which one(s) are superantigens?

Answer 13

A & C

Question 14

_____ _ is surface bound, a cysteine protease, and an adhesin that binds host laminin. it also leads to the production of IL-1, TNFa, IL-6, which all lead to _____.

Answer 14

SPE B

fever

Question 15

What is the function of streptokinase?

Answer 15

activates host plasminogen –> plasmin –> fibrin degradation (thus it degrades blood clots and further blocks the blood clotting response so that it can move more freely thru the host’s circulation)

Question 16

What age group is pharyngitis common in?

Answer 16

school age children 5-15 yrs

Question 17

What treatment is used to avoid complications of pharyngitis?

Answer 17

penicillin

Question 18

What is the immunological complication of pharyngitis?

Answer 18

acute rheumatic fever

Question 19

Fibrillar coiled-coil M protein share homology with _____.

Answer 19

myosin

Question 20

The host makes antibodies to the M protein of Group A strep, but the antibodies can cross react w/ ______. These antibodies are known as ____ _____.

Answer 20

myocardium (muscle of the heart)

x-reactive antibodies

Question 21

True or False: When acute rheumatic fever occurs, the individual may get life-long susceptibility to bacterial endocarditis.

Answer 21

True

Question 22

What is scarlet fever?

Answer 22

pharyngitis (strep) w/ a characteristic rash

Question 23

What leads to scarlet fever?

Answer 23

SPE intoxication

Question 24

What are symptoms associated w/ scarlet fever? (4 things)

Answer 24

punctate hemorrhages on soft & hard palate, strawberry tongue, red cheeks, circumoral pallor

Question 25

What is impetigo?

Answer 25

A form of transient skin colonization

Question 26

How is impetigo spread?

Answer 26

Direct contact w/ an infected individual, whether it be by indirectly touching the same items or directly contacting their lesions

Question 27

True or False: Impetigo is more common in young children, specifically of children aged 2-5yrs and in their face and lower extremities

Answer 27

True

Question 28

Impetigo is more often caused by __ ______, but increased by S. pyogenes

Answer 28

S. aureus

Question 29

What layer of skin does impetigo colonize?

Answer 29

superficial layers of skin (top skin layer)

Question 30

How are erysipelas and cellulitis different from impetigo?

Answer 30

They penetrate deeper into the dermis

Question 31

With erysipelas and cellulitis, the lesion is clearly demarcated and rapidly spreads. Where does infection frequently occur?

Answer 31

Face, often follows pharyngitis

Question 32

What are symptoms associated w/ erysipelas and cellulitis?

Answer 32

fever and enlargement of the lymph nodes

Question 33

When does acute glomerulonephritis occur?

Answer 33

1-4 weeks after pharyngitis and 3-6 weeks after skin infection

Question 34

The M protein of some nephritic strains share ______ similarity with _______ proteins

Answer 34

antigen | glomerulus

Question 35

Traditionally, only nephritogenic strains of group A strep pyogenes lead to ____ _________

Answer 35

acute glomerulonephritis

Question 36

What is the most severe complication from infection w/ Group A strep pyogenes?

Answer 36

Streptococcal Toxic Shock Syndrome (STSS)

Question 37

List the symptoms of STSS (3)

Answer 37

- muscular pain - chills - pain at focus of initial infection site

Question 38

When there is enhanced invasiveness into skin and soft tissue, the bacteria begin to distribute along lines of _____.

Answer 38

fascia

Question 39

What is necrotizing fasciitis?

Answer 39

Bacterial infection along our fascia that leads to death of the body's own tissue

Question 40

______ is part of our muscle and is part of what allows our muscle to move and flex without resistance or friction.

Answer 40

Fascia

Question 41

What are the symptoms of STSS? (5)

Answer 41

1. nausea 2. renal impairment 3. diarrhea 4. hypotension 5. shock --> organ damage