Skinny bacteria II Flashcards Preview

Microbio > Skinny bacteria II > Flashcards

Flashcards in Skinny bacteria II Deck (73):
1

What is the result for alpha, beta, and gamma hemolysis?

alpha = partial/green
beta = total
gamma = none

2

What are the lancefield antigens?

Cell wall carbs used to define beta-hemolytic into groups A through U

3

What is GAS?

S. Pyogenes

4

What is GBS?

S. agalactiae

5

What is GDS?

Enterococcus

6

What are the two groups of strep that do not get lancefield designations?

S. pneumoniae
S. mutans

7

What are the four major diseases GAS is responsible for?

Strep throat
Skin infections
Rheumatic fever
Glomerulonephritis

8

How do you differentiates GAS from other Beta hemolytic strep?

GAS is bacitracin sensitive

9

What are the three major virulence factors for GAS?

Hyaluronic acid capsule
Adhesins
Toxins

10

What is significant about that capsule of GAS

Hyaluronic acid is a poor immunogen (looks like self) and interferes with phagocytosis

11

What are the two toxins of GAS?

Streptolysin
Superantigens

12

What is the M protein found on Strep A? (3)

Myosin-like protein that:
-prevents phagocytosis
-allows for attachment
-Inhibits complement attack

13

What is the function of streptolysin O and streptolysin S?

Pore forming toxins

14

What percent of GAS produce superantigens?

10%

15

What are the superantigens that some strep produce? What are their function?

Pyrogenic exotoxins SpeA, SpeB, SpeC

Increase proinflammatory cytokine production

16

What is the function of C5a peptidase of GAS?

Prevents complement formation, and PMN chemotaxis

17

Strep gets into a cell using what protein? What happens then?

Streptolysin O

Produces more causing apoptosis of the cell

18

What are the four major skin infections caused by strep?

Impetigo (pyoderma)
Erysipelas
Cellulitis
Necrotizing fasciitis

19

How can you distinguish between staph and strep impetigo?

Staph is more extensive, with bullous lesions

20

Sharply demarcated erythematous skin = ?

Erysipelas

21

NOT sharply demarcated erythematous and warm skin = ?

Cellultis

22

What bacteria is the most common cause of cellulitis?

Strep pyogenes

23

GAS causes what % of necrotizing fasciitis?

60%

24

What are the symptoms of necrotizing fasciitis? (2)

Extreme pain/TTP
Grayish skin coloration initially, moving to erythema and edema

25

What is the treatment for necrotizing fasciitis?

Prompt debridement and removal of tissue

Broad spectrum Abx

26

What causes scarlet fever? Symptoms?

Strep pyogenes exotoxin Spe

Strawberry tongue
Petechial rash

27

Strawberry tongue + Petechial rash = ?

Scarlet fever

28

What are the complications of acute rheumatic fever? What causes it?

Heart valve tissue damage

d/t cross rxn w/ M protein and type II hypersensitivity

29

Glomerulonephritis is a complication of what?

Pharyngeal OR cutaneous GAS

30

What type of hypersensitivity is glomerulonephritis?

Type III

31

When does glomerulonephritis present?

1-4 weeks post GAS pharyngitis or 3-6 week post cutaneous infection

32

Symptoms of glomerulonephritis? (3)

Hematuria, HTN
Recent strep infx
Reduced serum complement

33

Strep toxic syndrome usually follow what disease?

Necrotizing fasciitis caused by strep

34

True or false: Strep toxic syndrome is the result of bacteremia

True

35

How do you diagnose GAS, besides serology and culture?

**Antistreptolysin O abs**

36

What is the treatment for GAS? Is staph susceptible to this?

PCN--staph would be resistant to this

37

What is the gram stain and morphology of pseudomonas aeruginosa? Hemolysis pattern? Oxidase? Ferment?

Gram negative motile rod
Beta hemolysis.
Oxidase positive
Non-fermenter

38

Is staph sensitive to PCN?

no, has beta lactamases

39

Where can pseudomonas grow?

Anywhere there is water--even soap

40

Blue green pigment on agar = ?

Pseudomonas aeruginosa

41

Pseudomonas aeruginosa usually are associated with what?

Recent hospitalization

42

True or false: Pseudomonas aeruginosa is an opportunistic pathogen, and has loads of abx resistance

True

43

What are the soluble pigments that Pseudomonas aeruginosa produces?

Pyocyanin
Pyoverdin

44

What is the capsule associated with Pseudomonas aeruginosa?

Alginate

45

What are the adhesins for Pseudomonas aeruginosa? (4)

Pili
Flagella
LPS
Alginate

46

What is the major exotoxin for Pseudomonas aeruginosa? Function? How is it administered to cells?

Exotoxin A
Blocks protein synthesis through inhibition of EF-2
Type III secretion system

47

What is the MOA of abx resistance for Pseudomonas aeruginosa?

Mutation of pore proteins

48

CF and burn patients hate what bacteria?

Pseudomonas aeruginosa

49

What is the common cause of swimmer's ear (otitis externa)?

Pseudomonas aeruginosa

50

What are the two major soft tissue infections that Pseudomonas aeruginosa causes?

Folliculitis
Osteochondritis

51

Pseudomonas aeruginosa infections are associated with what type of skin problem?

Burns

52

Bacteremia caused by Pseudomonas aeruginosa causes what?

Ecthyma gangrenosum

53

What is Ecthyma gangrenosum?

Necrotic skin lesions and infections of the blood vessels

54

What predisposes burns to Pseudomonas aeruginosa?

Moist surface + inability of PMNs to penetrate skin

55

What is Hot tub skin rash? Symptoms?

Pseudomonas folliculitis

Pruritic erythematous papules x5 days

56

What is the cause of "green nails"?

Pseudomonas aeruginosa biofilm/infection of the paronychia

57

What is webspace intertrigo? Cause?

Macerated and eroded skin on interdigital toes, usually caused by Pseudomonas aeruginosa

58

What is the treatment for Pseudomonas aeruginosa infections?

Combination therapy with aminoglycosides

59

What is the function of LTA that strep produces?

Involved in adhering to fibronectin on epithelial cell surfaces

60

What is the function of proteins F and M on strep?

F = adhesion

M = blocks C3b

61

What is the MOA of the superantigens produced by strep?

Increase proinflammatory cytokines

62

What is the function of DNAase that strep produces?

Depolymerizes DNA in pus, decreasing viscosity

63

What is the function of streptokinase produced by strep?

Cleaves plasminogen

64

Sharply demarcated erythema, with associated fever and chills = ?

Erysipelas

65

What is the pathogenesis of necrotizing fasciitis?

Dead tissue blocks circulation to the wound creating heaven for bacteria

66

What is the pathogeneis of rhemuatic fever heart damage?

Strep Pyogenes m M protein looks like heart tissue

67

Gram positive cocci in clusters = ? (usually)

Staph Aureus

68

Gram positive cocci in chain = ? (usually)

Strep Pyogenes

69

What are the symptoms of rheumatic fever? How long after a pharyngeal infx?

Diffuse, erythematous rash on upper chest, then extremities

Coating of the tongue (strawberry)

3 week post GAS pharyngitis

70

How do you distinguish between strep and staph toxic shock syndrome?

Staph = intoxication
Strep = bacteremia

71

Antibodies against streptolysin O (ASO test) is useful for confirming what disease(s)?

Rheumatic fever or glomerulonephritis

72

Can cutaneous infections of strep cause acute rheumatic fever?

No

73

TSST is produced by what bacteria?

Staph