Cmbm- Exam 3- Gram Positive Bacteria

Front 1

Which Staphylococcus toxin causes food poisoning?

Back 1

Enterotoxin A

*Enterotoxin is a Superantigen

Front 2

Which toxin causes 75% of menustration associated Toxic Shock Syndrome?

Back 2

TSST-1

*Superantigen

Front 3

Which 2 lab tests use enzymes to diagnose Staphylococcus aureus?

Back 3

1) Catalase test (differentiate from strep)
2) Coagulase test (differentiate from coagulase-negative strep)

Front 4

Why is growth on mannital-salt agar a useful diagnostic test for Staphylococcus aureus?

Back 4

Staph aureus is able to ferment mannitol

*Plate turns yellow

Front 5

Which antibiotics are all Staph resistant to?

Back 5

Penicillin

*Due to presence of b-lactamase
*Use semi-synthetic penicillin (nafcillin)

Front 6

What is the best prevention of Staph aureus?

Back 6

Good hand washing

*Immunity is short lived and incomplete so individuals can become re-infected!

Front 7

What types of Staphylococci are coagulase-negative?

Back 7

1) Staphylococcus epidermidis
2) Staphylococcus saprophyticus

Front 8

Which bacteria is found in the normal flora of the skin and is an opportunistic pathogen?

Back 8

Staph epidermidis

Front 9

Which bacteria is frequent cause of cystitis and is resistant to novobiocin?

Back 9

Staph saprophyticus

*It's resistance to novobiocin is used to distinguish it from S. aureus and S. epidermidis

Front 10

Which highly pathogenic bacteria is able to grow in high salt and lipid concentrations?

Back 10

Staph aureus

*Also hemolytic

Front 11

Which bacteria is both catalase and coagulase positive?

Back 11

Staph aureus

Front 12

What enzyme distinguishes Staph from Strep?

Back 12

Catalase

*Staph (+) ; Strep (-)

Front 13

Which bacteria causes more varied diseases than any other pathogen?

Back 13

Staphylococcus aureus

Front 14

List 3 clinical manifestations of Staph aureus

Back 14

1) Folliculitis
2) Furuncle
3) Carbuncle
4) Impetigo (Bullous)
5) *Osteomyelitis
6) *Septic arthritis

Front 15

Which two Syndromes are manifested by Staph aureus toxins?

Back 15

1) Staphylococcal Scalded Skin Syndrome (exfoliation toxin)
2) Toxic Shock Syndrome (TSST-1 or enterotoxin)

Front 16

Name the three Staph aureus surface components that increase its virulence

Back 16

1) Capsule and slime
2) Protein A
3) Fibronectin binding protein (Teichoic acid)

Front 17

What classes of strep are included in the group A and B Lancefield groupings?

Back 17

Group A- S. pyogenes (GAS or GABHS)
Group B- S. agalactiae (GBS)

Front 18

What are the three ways to classify Streptococci bacteria?

Back 18

1) Lancefield grouping (based on major cell wall carbohydrates)
2) Hemolysis patterns
3) Species

Front 19

What does it mean if a bacteria is classified as alpha-hemolytic?

Back 19

Incomplete hemolysis

*beta-> complete hemolysis
*gamma-> no hemolysis

Front 20

Which Strep bacteria is B-hemolytic and Bacitracin sensitive

Back 20

Strep pyogenes (GAS)

Front 21

What makes the pili of Strep pyogenes unique?

Back 21

The pili contains M-protein

*Involved in adhesion, antiphagocytic

Front 22

Which toxin is responsible for the rash seen in scarlet fever?

Back 22

Strep Pyrogenic Exotoxin

*Superantigen -> Cytokine storm

Front 23

How would you test for previous Strep infection?

Back 23

Test for antibodies against Streptolysin O or other enzymes

Front 24

What is the number one cause of pharyngitis?

Back 24

Strep pyogenes

*Scarlet fever is result of Strep pharyngitis producing exotoxins

Front 25

List 3 suppurative diseases caused by Strep pyogenes

Back 25

1) Pharyngitis
2) Scarlet fever
3) Impetigo
4) Erysipelas
5) Cellulitis
6) Necrotizing Fasciitis (Strep gangrene)
7) Streptococcal Toxic Shock Syndrome

Front 26

What are the 2 non-suppurative complications caused by Strep pyogenes?

Back 26

1) Acute Rheumatic Fever
2) Acute Glomerulonephritis

Front 27

How would you diagnose Strep pyogenes?

Back 27

1) Catalase negative
2) Sensitivity to bacitracin and CAMP negative (distinguish from GBS)

*Prompt antibiotic treatment will prevent initial attach of rheumatic fever (but not glomerulonephritis)

Front 28

What distinguishes Group A and Group B Streptococci?

Back 28

Group B is resistant to Bacitracin

*Group B also have larger colonies and a narrower zone of hemolysis

Front 29

What type of bacteria is a leading cause of neonatal sepsis and meningitis?

Back 29

Streptococcus agalactiae (GBS)

*60% infants born to colonized mothers become colonized

Front 30

What are the three diagnostic tests to distinguish Strep agalactiae (GBS)

Back 30

1) Hippurate hydrolysis (other B-hemolytic strep lack hippuriase)
2) (+) CAMP Test (GAS are (-))
3) Bacitracin resistant (GAS are sensitive)

Front 31

Which class of bacteria were part of group D Streptococci and are VERY resistant to commonly used antibiotics?

Back 31

Enterococcus

*VERY resistant to commonly used antibiotics!

Front 32

What distinguishes Enterococcus from other catalase negative gram (+) bacteria?

Back 32

Enterococcus can grow in 6.5% NaCl and in the presence of 40% bile salts and hydrolyze esculin

Front 33

Which class of bacteria causes sub-acute bacterial endocarditis?

Back 33

Viridans Streptococci

*S. Mutans causes dental carries

Front 34

Which class of Strep is optochin sensitive and is lysed by bile (bile soluble)?

Back 34

Strep pneumoniae