Skin

Question 1

Stain, shape, motility, metabolism of Staph

Answer 1

gram positive
cocci
nonmotile
facultative anaerobes

Question 2

Where are staphlococci found in humans?

Answer 2

surface tissue, GI tract, especially anterior nares

Question 3

What is the fxn of coagulase?

Answer 3

converts fibrinogen to fibrin

Question 4

How do you differentiate Staph from Strep?

Answer 4

Staph are catalase positive

Question 5

What is unique to Staph aureus

Answer 5

protein A

Question 6

What does Protein A do?

Answer 6

binds Fc portion of IgG and the IgG can no longer contribute to opsonization and phagocytosis

Question 7

How do the different diseases of S aureus come about?

Answer 7

different strains have different toxins

Question 8

What are the toxins made by S aureus?

Answer 8

Hemolysins
Leukotoxins
Enterotoxins (superantigens)
TSST
Exfoliative toxins

Question 9

What type of hemolysin are those of S aureus?

Answer 9

Beta hemolytic

Question 10

What are the superantigens made by Staph aureus?

Answer 10

enterotoxins and TSST

Question 11

What are exfoliative toxins?

Answer 11

Proteases that lyse intercellular connections between cells in the epidermis

Question 12

How are Staphylococcus transmitted?

Answer 12

mostly by hand contact

Question 13

Where are the primary sites of infection for Staphylococcus aureus

Answer 13

skin

Question 14

What kinds of infection can Staphylococcus aureus cause?

Answer 14

folliculitis
boil (subcutaneous)
impetigo
scalded skin syndrome
pneumonia
osteomyelitis
arthritis

Question 15

How do you treat S. aureus infections?

Answer 15

drain the wound
remove foreign objects
antibiotics

Question 16

Where do S saprophyticus infections usually occur?

Answer 16

urinary tract

Question 17

Stain, shape, metabolism of Streptococci

Answer 17

gram positive
cocci
facultative anaerobe (ferment carbs–lactic acid made)

Question 18

How are Streptococci classified?

Answer 18

Lancefield typing based on cell wall carbohydrate antigen
Hemolytic abilities on blood agar (alpha is partial or green, beta is complete clearing, gamma is no clearing)
Biochemical properties

Question 19

What is S agalactiae known for?

Answer 19

neonatal disease

Question 20

What is S pyogenes known for?

Answer 20

pharyngitis, rheumatic fever, glomerulonephritis, tissue infections

Question 21

What is S pneumoniae known for?

Answer 21

otitis media, pneumonia, sepsis, meningitis

Question 22

What is S bovis known for?

Answer 22

bacteremia linked to GI cancer

Question 23

What do Streptococcus pyogenes have?

Answer 23

Lanceefield Group A carb
M proteins
M-like surface proteins
Lipotenichoic acid and F protein that help with adhering
Hyaluronic acid capsule
C5a peptidase

Question 24

pathogenesis of strep pyogenes

Answer 24

avoids opsonization and phagocytosis (hyaluronic acid capsule
adheres to host cells (lipoteichoic acid, M proteins, F protein)
Invasion of host cells (M and F proteins)
Toxins and enzymes (exotoxins are superantigens)

Question 25

What kinds of hemolysins does S pyogenes make?

Answer 25

Streptolysin S, Streptolysin O

Question 26

Where is S pyogenes found?

Answer 26

transiently in oropharynx of healthy kids and adults

Question 27

How can you tell that someone is protected from S pyogenes?

Answer 27

has antibodies to M protein

Question 28

How is S pyogenes spread?

Answer 28

droplet transmission

Question 29

What kind of clinical diseases do you see w Strep pyogenes?

Answer 29

``` pharyngitis Scarlet fever (pharyngitis and erythematous rash) impetigo/pyoderma erysipelas (skin and subcu) toxic shock endocarditis necrotizing fasciitis ```

Question 30

Group A late sequalae

Answer 30

rheumatic fever-after respiratory infections(strep antigens cross react) glomerulonephritis-after pharyngela or cutaneous infections

Question 31

What confirms rheumatic fever or glomeurolonephritis?

Answer 31

antibodies to streptolysin O

Question 32

Pathogenesis of strep agalactiae

Answer 32

Capsule

Question 33

Where does strep agalactiae colonize?

Answer 33

lower GI tract and genitourinary tract-can be given to neonates

Question 34

What kinds of diseases do strep agalactiae cause?

Answer 34

neonatal meningitis, pneumonia, sepsis Sepsis in pregnant women in older adults (bacteremia, pneumonia, bone and joints, skin and soft tissue)

Question 35

Stain, shape, hemolysis of Strep penumonia

Answer 35

gram positive coccus alpha hemolytic

Question 36

How do you ID strep pneumonia?

Answer 36

alpha hemolytic polysaccharide capsule phosphorylcholine and species specific teichoic acid cell wall C polkysaccharide-binds C reactive protein F antigen--reacts with Forssman surface antigen on human cells

Question 37

Pathogenesis of strep pneumonia

Answer 37

mostly as a result of host response, not toxins binds to oropharynx releases toxic cell wall components (teichoic acids, peptidoglycan)

Question 38

How does S penumonia infection come about?

Answer 38

S pneumonia transiently colonzes normal people Can be aspirated in lower airway linked to breakdown of natural defenses (epiglottal reflex, cough reflex)

Question 39

Clinical diseases of strep pneumonia

Answer 39

``` pneumococcal pneumonia (blood in sputum, cough, chest pain, fever) Sinusitis and otitis media Meningitis Bacteremia Endocarditis ```

Question 40

Prevention of streptococcus pneumonia

Answer 40

adults and children greater than 2=vaccine with 23 capsular polysaccharides

Question 41

chemical test for s pneumoniae

Answer 41

optochin sensitive

Question 42

chemical test for s pyogenes

Answer 42

bacitracin sensitive

Question 43

Panton valentine leukocidin is associated with___

Answer 43

staph aureus, present in many MRSA infections